



WARNING

THIS IS AN APPEAL UNDER THE

YOUTH CRIMINAL JUSTICE ACT

AND IS SUBJECT TO:

111(1)        
    Subject to this section, no person shall publish the name of a child or young
    person, or any other information related to a child or a young person, if it
    would identify the child or young person as having been a victim of, or as
    having appeared as a witness in connection with, an offence committed or
    alleged to have been committed by a young person.

138(1)        
    Every person who contravenes subsection 110(1) (identity of offender not to be
    published), 111(1) (identity of victim or witness not to be published), 118(1)
    (no access to records unless authorized) or 128(3) (disposal of R.C.M.P.
    records) or section 129 (no subsequent disclosure) of this Act, or subsection
    38(1) (identity not to be published), (1.12) (no subsequent disclosure), (1.14)
    (no subsequent disclosure by school) or (1.15) (information to be kept
    separate), 45(2) (destruction of records) or 46(1) (prohibition against disclosure)
    of the
Young Offenders Act
,
    chapter Y-1 of the Revised Statutes of Canada, 1985,

(a) is guilty of an
    indictable offence and liable to imprisonment for a term not exceeding two
    years; or

(b) is guilty of an
    offence punishable on summary conviction.




COURT OF APPEAL FOR ONTARIO

CITATION: R. v. Oppong, 2021 ONCA 352

DATE: 20210525

DOCKET: C65486 & C64579

Rouleau, van Rensburg and Miller
    JJ.A.

BETWEEN

Her Majesty the Queen

Respondent

and

Derek Oppong

Appellant

AND BETWEEN

Her Majesty the Queen

Respondent

and

Akido Thomas

Appellant

Dirk Derstine, for the appellant Derek
    Oppong

Akido Thomas, appearing in person

Geoff
    Haskell, for the appellant Akido Thomas, pursuant to a limited order under s. 684
    of the
Criminal Code

Amy Alyea,
    for the respondent

Heard: January 14,
    2021 by video conference

On appeal
    from the conviction entered on June 8, 2017 by Justice Robert F. Goldstein of
    the Superior Court of Justice, sitting with a jury, and the sentence imposed on
    November 6, 2017, with reasons reported at 2017 ONSC 6684 (C65486).

On appeal
    from the conviction entered on June 8, 2017 by Justice Robert F. Goldstein of
    the Superior Court of Justice, sitting with a jury (C64579).

van Rensburg J.A.:

I

OVERVIEW

[1]

The appellants and a co-accused, Raheem Thomas-Stewart,
    were tried before judge and jury and convicted of having committed various kidnapping-related
    offences with a firearm at the direction of or for the benefit of a criminal
    organization. Mr. Oppong was acquitted of attempted murder. Mr. Oppong was
    sentenced to 11 years in prison, less credit for four years pre-sentence
    custody. Mr. Thomas was sentenced to nine years, less credit for 52 months
    pre-sentence custody.

[2]

Mr. Oppong appeals his conviction and seeks to
    appeal his sentence. Mr. Thomas appeals only his conviction, having withdrawn
    his sentence appeal at the hearing of the appeal. Mr. Thomas was represented by
    counsel on a limited retainer under s. 684 of the
Criminal Code
, R.S.C. 1985, c. C-46
.

[3]

On their conviction appeals the appellants
    assert that the trial judge erred in admitting the opinion evidence of an
    expert witness relating to gang activity and discipline. They say that the
    trial judge erred in admitting the experts evidence, which was unnecessary and
    biased, and in failing to find that its prejudicial effect outweighed its
    probative value. In the alternative, they contend that the trial judge erred in
    refusing to exclude the expert evidence after a material change in
    circumstances: the proposed admission of certain facts that obviated the need
    for the expert evidence.

[4]

In his sentence appeal, Mr. Oppong asserts that the
    trial judge made a finding that was not supported by the evidence  that he was
    a leader of a street gang called In Da Streets (IDS). Without this finding,
    he contends that he ought to have received the same sentence as Mr. Thomas.
[1]

[5]

For the reasons that follow, I would dismiss the
    conviction appeals and the sentence appeal.

[6]

As I will explain, the trial judge made no
    reversible error in admitting the expert evidence in this case. He addressed
    the concerns raised by the defence, and exercised appropriate caution in
    admitting some, but not all, of the proposed expert evidence, and in limiting
    the specific items the expert was permitted to rely on when testifying, in
    order to avoid prejudice to the accused. The trial judge did not err in refusing
    to exclude the expert evidence on the basis of a material change in
    circumstances after the appellants counsel indicated that the appellants were
    prepared to admit certain facts. He reasonably concluded that the facts the
    appellants were prepared to admit did not alter the balance between the
    prejudicial effect and probative value of the expert evidence.

[7]

As for the sentence appeal, contrary to Mr.
    Oppongs argument, there was evidence to support the conclusion that he was a
    leader of IDS, and his sentence was entirely fit.

[8]

In the reasons that follow, I will address the
    issues raised in the conviction appeals and then I will turn to Mr. Oppongs
    sentence appeal.

II

CONVICTION APPEALS

A.

THE OFFENCE

[9]

The charges arose out of an alleged incident
    between the appellants, their co-accused, and Dontay Haye, while they were all members
    of IDS, a street gang that operated in the Toronto neighbourhood of Jamestown.

[10]

Mr. Haye, who was 16 years old at the time,
    claimed that on May 19, 2015 he was warned by friends that people were looking
    for him because they believed he had stolen one of the guns belonging to the
    gang. They suspected that Mr. Haye had taken the gun because he knew that
    the gun was normally hidden in a BBQ grill near the home of Mr. Hayes best
    friend, A.M. Mr. Haye claimed that, as he was walking through the neighbourhood,
    he was approached by Mr. Thomas and Mr. Thomas-Stewart, who punched him in the
    face and chest. Mr. Thomas had a handgun and threatened to shoot him. They
    forced Mr. Haye to follow them to John Garland Blvd., where they met up with
    Mr. Oppong and several other men who assaulted him again. Mr. Oppong kept
    asking him where the gun was, and Mr. Haye kept saying that he did not
    have it.

[11]

After the second assault, Mr. Oppong told Mr.
    Haye to get into a car. He drove Mr. Haye to a housing complex where Mr. Oppong
    told him that he could either bring back the gun or give him $2,500, or else he
    would be flipped (i.e.: killed). They walked toward a field near the housing
    complex where they were joined by A.M., who had a gun. Mr. Oppong told Mr. Haye
    that this was his last chance. As Mr. Haye started to run away, Mr. Oppong told
    A.M. to chase after and to shoot him. A.M. chased after Mr. Haye, but he did
    not shoot. Mr. Haye managed to escape. He ran to a nearby townhouse unit where
    he persuaded the occupant to call 911.

[12]

Mr. Haye eventually entered the witness
    protection program and provided his account of the events to the police.

[13]

The movements of the parties were captured by
    CCTV cameras. The defence theory at trial was that Mr. Haye fabricated the
    story about having been assaulted, threatened and kidnapped. The accused did
    not testify. The central issue was the credibility and reliability of Mr.
    Hayes account.

B.

THE EXPERT EVIDENCE

The Admissibility Ruling

[14]

The Crown brought a pre-trial application
    seeking to admit expert opinion evidence from Detective Aman Nasser,
[2]
a Toronto police officer with considerable experience and knowledge of street
    gangs in Toronto.

[15]

The Crown proposed that Detective Nasser would
    testify about the IDS gang and the general nature and activities of urban
    street gangs and their characteristics as criminal organizations within the
    definition of that term in s. 467.1(1) of the
Criminal Code.
Detective
    Nasser had prepared an expert report, in which he responded to three questions:
    (1) is IDS a street gang; (2) would IDS benefit from kidnapping Mr. Haye; and
    (3) are Mr. Oppong, Mr. Thomas, and Mr. Thomas-Stewart members of IDS?

[16]

The Crown argued that the expert evidence was
    required to demonstrate essential elements of the criminal organization
    offences: that IDS is a criminal organization and that the kidnapping and
    assault of Mr. Haye would have benefited IDS. The Crown also submitted that the
    evidence assisted in understanding the context or narrative of the alleged
    offences.

[17]

The application was opposed by the defence on
    the basis that the proposed expert evidence failed to meet the first two
Mohan
criteria of necessity and relevance:
R. v. Mohan
, [1994] 2 S.C.R.
    9. They asserted that the evidence was unnecessary because Mr. Haye would be
    able to provide all the evidence needed to show that IDS is a street gang, and
    that the issues in the case went to credibility and were not such that the jury
    required additional context. The defence also argued for the exclusion of the
    evidence at the gatekeeper stage  that the probative value of the proposed
    expert evidence was outweighed by its prejudicial effect, failing the
    cost-benefit analysis set out in
R. v. Abbey
, 2009 ONCA 624, 97 O.R.
    (3d) 330, leave to appeal refused, [2010] S.C.C.A. No. 125.

[18]

The application to introduce expert evidence,
    which included a
voir dire
in which the proposed expert testified, was
    heard over the course of four days. The trial judge provided an oral ruling in
    which he concluded that Detective Nassers expert evidence was admissible,
    although he limited the scope of such evidence. He provided a table of specific
    rulings on the admissibility of certain items of evidence that the expert could
    or could not refer to in his testimony.

[19]

In the trial judges written reasons (reported
    at 2017 ONSC 3443), he concluded that the proposed expert evidence met the four
Mohan
criteria. He noted that defence counsel had conceded that
    Detective Nasser was a properly qualified expert and that there was no
    exclusionary rule that applied. In addressing the two contested criteria, the
    trial judge found that the proposed evidence was logically relevant and
    necessary. He stated:

I find that the evidence is logically relevant
    to [the] facts in issue: [
Abbey
], at para. 84. The characteristics of
    street gangs and street gang ideology are relevant to understanding the context
    of the alleged offences. The expert evidence is also relevant to whether the
    assault and kidnapping of Mr. Haye (if his evidence is believed) was for the
    benefit of a criminal organization. Without the expert evidence, the jury will
    be left solely with the evidence of Dontay Haye. Dontay Haye may or may not
    give evidence regarding the use of violence by gangs to enforce discipline and
    communicate a message of obedience to the gang hierarchy.

Furthermore, Mr. Hayes evidence is problematic,
    to say the least. Mr. Hayes credibility will undoubtedly be subject to
    sustained assault in all respects. Without the context provided by the expert
    evidence, the jury will be left with his version of how gangs operate. The jury
    may well be left to puzzle over the purpose of an attempt to kidnap and beat
    Mr. Haye without context. The expert evidence will assist in evaluating his
    credibility (or lack of credibility).

[20]

The trial judge then assessed whether the
    probative value of the proposed evidence outweighed its prejudicial effect. He
    recognized that the gatekeeper function does not involve bright lines and
    that it requires an analysis of costs and benefits and sometimes does not
    yield a straightforward yes or no answer (citing
Abbey
, at para.
    79 and
R. v. Sheriffe
, 2015 ONCA 880, 333 C.C.C. (3d) 330, at paras.
    101-103, 108, leave to appeal refused, [2016] S.C.C.A. No. 299). The trial judge
    reviewed a number of case authorities with respect to the assessment of the
    costs and benefits of evidence relating to gangs:
Abbey
;
R. v.
    Riley
, [2009] O.J. No. 1374 (Ont. Sup. Ct.);
R. v. Williams
, 2013
    ONSC 1076. He noted that the assessment of the probative value of expert
    evidence involves consideration of the significance of the particular issue, as
    well as the reliability of the evidence, including the experts methodology,
    expertise and objectivity, while the cost of the evidence addresses the usual
    risk of prejudice in expert evidence, as well as the risk of complexity and the
    abdication of the jurys function to the expert. The trial judge observed that
    proving criminal organization offences would inevitably involve bad character
    evidence. As such, steps must be taken to limit the evidence to what is
    relevant and necessary, and to give mid-trial and final instructions to place
    the evidence in context and obviate prejudice.

[21]

In assessing the probative value of the
    evidence, the trial judge addressed defence counsels argument that Detective
    Nasser had shown a lack of objectivity because (1) he did not wish to engage
    with defence counsel on a particular issue outside the courtroom setting; and (2)
    his background work into certain incidents of gang association or indicia of
    gang membership involving the accused did not go far enough. The trial judge adverted
    to these concerns about Detective Nassers evidence and concluded that they
    would go to the weight to be given to his opinion by the jury.

[22]

The trial judge limited the scope of the expert
    evidence. Detective Nasser was permitted to testify about the general
    characteristics of a street gang, the association of street gangs with
    particular neighbourhoods, methods that gang members use to identify themselves
    as members, gang ideology, and the use of violence by gangs to maintain
    discipline. He was not permitted to state as a fact that any of the three
    accused were members of IDS, although he was allowed to testify about
    particular associations, symbols and incidents that were consistent with
    membership in IDS or a street gang. Detective Nasser was not allowed to testify
    that the alleged kidnapping, assault and attempted murder of Mr. Haye
    would have benefitted IDS. The trial judge addressed the extent to which Detective
    Nasser could rely on confidential informant information, and he provided specific
    rulings on certain aspects of Detective Nassers proposed evidence, including
    the extent to which the expert was permitted to refer to various incidents involving
    gang members (including the appellants) and YouTube videos.

The Application to Revisit the
    Admissibility Ruling

[23]

Before the trial proper began, and upon receipt
    of the trial judges written reasons, Mr. Oppongs trial counsel raised the
    possibility of making certain concessions if the Crown agreed not to call
    Detective Nasser as a witness. The following day the trial judge heard a
    defence application to revisit his admissibility ruling based on a material
    change in circumstances, in light of the proposed admissions.

[24]

The appellants were prepared to admit that IDS
    existed, that Mr. Oppong and Mr. Thomas were members of IDS, and that the
    acts (if they took place) were committed at the behest of a criminal
    organization. Mr. Thomas-Stewart was prepared to admit that IDS is a street
    gang, that association with other members is a characteristic of gang
    membership, and that he was in the company of certain gang members on specific
    dates (not including the date of the incident).

[25]

Defence counsel argued that the proposed
    admissions extended beyond the scope of Detective Nassers permitted evidence and
    constituted a material change in circumstances. They asserted that with these
    admissions, the probative value of Detective Nassers evidence would need to be
    re-assessed, as it would now only serve to bolster Mr. Hayes credibility.
    Counsel for Mr. Oppong also proposed that, if necessary, evidence on the
    general characteristics and circumstances of street gangs could be provided
    through an agreed statement of facts, although no agreement had been reached.

[26]

The trial judge gave a brief oral ruling dismissing
    the application to revisit his ruling on the expert evidence, with written
    reasons released subsequently and reported at 2020 ONSC 7844.

[27]

The trial judge concluded that there was no
    basis to revisit his admissibility ruling. He stated that the willingness of
    the defence to make some admissions did not constitute a material change of
    circumstances. Citing the trial decision in
R. v. Gager
, 2012 ONSC
    2697 (where a trial judge had revisited a ruling with respect to what evidence
    an expert on gangs could refer to in his evidence), the trial judge noted that,
    in order for the change of circumstances to be material, it must alter the
    balance between the prejudicial effect and probative value of the evidence.

[28]

The trial judge observed that there was a
    significant difference between admitting facts pursuant to s. 655 of the
Criminal
    Code
and admitting the thrust of expert evidence that goes to assisting
    the jury in understanding the context of the case. He noted that the factual admissions
    the defence proposed to make did not assist the jury in understanding the
    context of Mr. Hayes evidence. He concluded: The key point about [Detective]
    Nassers evidence is that it is supposed to help the jury understand the
    background. The proposed admissions do nothing to advance the jurys
    understanding without context.

[29]

The trial judge rejected the submission of Mr.
    Thomass counsel that the expert evidence was simply an attempt at
    oath-helping. He noted: As I stated in my original ruling, the purpose of the
    expert evidence was to allow the jury to understand his evidence given the
    circumstances of a gang-related offence. He went on to observe that, even if
    he had accepted that the proposed admissions were a material change, there
    would have been great difficulties in managing the trial where one of the
    accused was not prepared to make the same admissions as the other two.

[30]

As for the argument that the general
    characteristics and circumstances of street gangs could be addressed through an
    agreed statement of facts, the trial judge observed that there was no such agreement,
    and that he had no power as a trial judge to compel a party to make a
    concession it was not otherwise prepared to make.

The Expert Evidence at Trial

[31]

Detective Nasser was the Crowns first witness at
    trial. In the course of his evidence, counsel for Mr. Oppong conceded his
    clients membership in IDS and the Crown refrained from eliciting evidence from
    Detective Nasser regarding some (but not all) incidents in which Mr. Oppong was
    associating with known gang members. After Mr. Thomass counsel conceded his
    clients membership in IDS, the Crown refrained from eliciting evidence from
    Detective Nasser regarding Mr. Thomass forearm tattoo, and that it was
    consistent with gang membership, as well as some (but not all) incidents in
    which Mr. Thomas was observed associating with known gang members. Detective
    Nasser was cross-examined, but only by counsel for the appellants co-accused, Mr.
    Thomas-Stewart.

[32]

The jury charge included a general instruction on
    Detective Nassers expert opinion evidence, including that he had been
    qualified by training and experience to give an expert opinion regarding the
    nature and characteristics of street gangs, and cautioning the jury against the
    use of underlying information relied on by the expert, that was not in
    evidence. The trial judge provided a specific instruction on evidence of
    membership in a street gang that strongly warned against propensity reasoning.
    The trial judge reminded the jury that they heard evidence about the nature and
    characteristics of street gangs to understand the evidence in relation to
    criminal organization offences and to understand how gangs work and what their
    purpose is, in order to place the evidence in context. On each occasion that the
    trial referred to such evidence, he reminded the jury of the importance of not
    using the evidence improperly. There was no objection to these instructions.

C.

ISSUES

[33]

The appellants raise two issues on their
    conviction appeals:

1.

Did the trial judge err by allowing the Crown to
    tender a gang expert who was both unnecessary and biased?

2.

Did the trial judge err by admitting the gang
    expert evidence after a material change in circumstances?

[34]

Deference is owed to a trial judges decision on
    admitting expert evidence absent an error in principle, a material apprehension
    of evidence or an unreasonable conclusion:
R. v. Mills
, 2019 ONCA 940,
    151 O.R. (3d) 138, at para. 47;
R. v. McManus
, 2017 ONCA 188, 353
    C.C.C. (3d) 493, at para. 68. It is only where such an error is demonstrated
    that this court can interfere. In other words, the role of this court is not to
    take a fresh look at the admissibility of the expert evidence, and to arrive at
    its own conclusion.

[35]

The appellants acknowledge that the trial judge
    identified the proper criteria and purported to apply the correct framework in
    determining the admissibility and scope of Detective Nassers opinion evidence
    when he made his initial ruling. They argue however that he erred in the
    application of the
Mohan
framework. Essentially, they contend that the
    trial judge erred in concluding  both at the initial stage and in weighing the
    probative value against the prejudicial effect of Detective Nassers evidence 
    that the expert evidence was necessary and impartial.

[36]

The appellants also contend that the trial
    judge, in refusing to reopen his ruling in the light of certain admissions they
    were prepared to make, erred in principle by failing to find a material change
    in circumstances. I will address these arguments in turn.

D.

DISCUSSION

(1)

The applicable framework

[37]

I begin by referring to the framework for the
    determination of admissibility of expert opinion evidence, including expert
    evidence about gangs. It is important to keep certain general principles in
    mind.

[38]

Trial judges have the responsibility to act as
    gatekeepers in deciding whether to admit any expert evidence, in determining
    its scope and in ensuring that the expert evidence remains within its proper
    bounds at trial. Depending on how the trial unfolds, an admissibility ruling
    may need to be revisited. In jury trials, the judge will need to provide
    appropriate instructions so that the jury understands the limits on the
    permitted uses of the expert evidence:
Mohan
, at p. 24.

[39]

The
Mohan
framework involves a two-step
    approach to determining the admissibility of expert evidence. At the first, or
    threshold, step, the court considers the four criteria of (1) whether the
    expert is properly qualified; (2) whether the evidence is affected by an
    exclusionary rule (other than the opinion rule itself); (3) whether the
    evidence is logically relevant to issues in the proceeding; and, (4) whether
    the expert evidence is necessary. The second, or gatekeeper stage requires
    the judge to balance the potential risks and benefits of admitting the
    evidence:
White Burgess Langille Inman v. Abbott and Haliburton Co.
,
    2015 SCC 23, [2015] 2 S.C.R. 182, at paras. 19, 22-24;
R. v. Sekhon
,
    2014 SCC 15, [2014] 1 S.C.R. 272, at paras. 43-44, 46-47;
R. v. J.(J.-L.)
,
    2000 SCC 51, [2000] 2 S.C.R. 600, at para. 28.

[40]

Ontario courts are frequently called upon to
    apply the
Mohan
criteria to determine the admissibility and scope of
    expert evidence concerning gangs. As this court noted in
R. v. Phan
, 2020
    ONCA 298, 387 C.C.C. (3d) 383, at para. 91, the case law is replete with the
    admission of gang evidence for the purpose of providing context or narrative,
    to establish
animus
or motive, to establish the accuseds state of
    mind or intention, or for other purposes.

[41]

At the same time, the cases recognize the risks
    associated with the admission of expert evidence concerning gangs. The primary
    danger arising from the admission of any opinion evidence is that the jurors
    function as fact-finders might be usurped by that of the witness:
R. v. D.(D.)
,
    2000 SCC 43, [2000] 2 S.C.R. 275, at para. 53. A particular risk of expert evidence
    concerning gangs is the potential for bad character propensity reasoning. Bad
    character evidence itself is presumptively inadmissible unless the Crown can
    demonstrate that it is relevant to an issue in the case, and its probative
    value outweighs its prejudicial effects. The evidence is inadmissible if it serves
    only to show that an accused is the type of person likely to have committed the
    offence:
R. v. B., (F.F.)
, [1993] 1 S.C.R. 697, at pp. 699, 731;
Phan
,
    at paras. 90-91;
R. v. G. (S.G.)
, [1997] 2 S.C.R. 716, at para. 65.

[42]

Trial judges decide on the need for expert
    evidence and weigh the probative value of the evidence against its prejudicial
    effect in the context of the live issues at trial, with the advantage of hearing
    the evidence in issue, observing the jury and being able to appreciate the
    dynamics of the particular trial:
D.(D.)
, at paras. 12-13. Ultimately
    the admissibility of any expert opinion evidence is highly case-specific:
R.
    v. Gager
, 2020 ONCA 274, at para. 27, leave to appeal to S.C.C. refused, 39477
    (April 22, 2021).

(2)

The initial admissibility ruling: Did the trial judge
    err in admitting evidence that was unnecessary and biased?

(a)

Necessity

[43]

The appellants assert that the trial judge erred
    in concluding that the
Mohan
criterion of necessity was met in this
    case. They make two arguments. First, they say that Mr. Hayes narrative and the
    issues in this case were not complicated or technical, such that the jury needed
    expert evidence to understand the context or motive for the alleged offence. It
    was obvious that the appellants and Mr. Haye were all members of a particular
    gang, and there was no need for an expert to explain to a jury why a street
    gang would want its gun back. Second, they argue that Detective Nassers evidence
    was made redundant by Mr. Hayes testimony. Unlike many other cases where the
    victim was deceased or unavailable, and expert evidence was needed to fill
    gaps in the evidence, Mr. Haye could testify about the existence of the gang,
    gang membership and culture.

[44]

The Crown contends that the trial judge did not
    err in determining that the expert evidence was necessary. There were many aspects
    of the evidence that fell outside the common knowledge of the jury, and outside
    Mr. Hayes evidence. Mr. Hayes testimony would not address whether the alleged
    acts were committed for the benefit of IDS, and whether IDS was a criminal
    organization. Moreover, Detective Nassers evidence provided the necessary
    factual context for the jury to be able to evaluate Mr. Hayes narrative. The
    Crown argues that the evidence was essential to the jurys ability to consider
    Mr. Hayes account in the proper context and to fairly assess whether the
    attack on him occurred for the benefit of a gang.

[45]

To meet the
Mohan
criterion of
    necessity, the question is whether the expert will provide information which is
    likely outside the ordinary experience and knowledge of the trier of fact:
D.(D.)
,
    at para. 21. The subject-matter of the inquiry must be such that ordinary
    people are unlikely to form a correct judgment about it, if unassisted by
    persons with special knowledge:
R. v. Johnson
, 2019 ONCA 145, 145
    O.R. (3d) 453, at paras. 53, 66. Expert evidence is not necessary if triers of
    fact can form their own conclusions without help because to do otherwise risks
    abdicating the role of deciding the facts to the expert:
Sekhon
, at
    paras. 45, 49. Necessity means that the evidence must be more than merely
    helpful, but necessity need not be judged by too strict a standard:
Mohan
,

at p. 23.

[46]

The trial judge adverted to these relevant
    principles in his reasons for admitting and setting the parameters for the expert
    evidence in this case. He concluded that the opinion evidence of Detective
    Nasser was necessary in the sense the evidence spoke to matters that were
    beyond the ordinary experience of the jury, and he rejected the assertion that
    the Crown should have to rely on Mr. Haye, who was an admitted gang
    member, to provide such evidence.

[47]

I see no error in the trial judges conclusion
    that the expert evidence of Detective Nasser, as limited in scope by his
    ruling, was necessary, or in his conclusion that the fact that Mr. Haye would
    be testifying did not obviate the need for the evidence.

[48]

First, I reject the contention that the matters
    to which the evidence was addressed were within the ordinary scope of
    understanding or experience of the jury. The offences were said to have been
    for the benefit of a criminal organization. It would have been wrong for the
    jury to rely on their own beliefs based on anecdotal experience and popular
    media about gang ideology and membership. Detective Nassers depth of knowledge
    and the fact that he was qualified as an expert to provide opinion evidence
    were readily acknowledged by the defence. The various matters about which he
    was permitted to testify  including the methods gang members used to identify
    themselves as members, the characteristics consistent with gang membership such
    as close associations with a known gang member, jewellery and tattoos, gang
    ideology, including discipline and the use of violence  were without question
    outside the ordinary experience and knowledge of the [jury as] trier of fact.
    The determination of what matters fall within the normal experience of jurors
    falls squarely within the trial judges domain:
R. v. Boswell
, 2011
    ONCA 382, 277 C.C.C. (3d) 156, at para. 29.

[49]

I see no error in the trial judges conclusion
    that the jury needed the expert evidence as part of its assessment of whether
    the offences were committed for the benefit of a criminal organization, and to
    understand the context of what happened. While the necessity of expert evidence
    is case-specific, in several cases trial judges have accepted that the jury
    required expert evidence about aspects of gang culture that are not widely
    known, in order to understand the context in which the central events took place:
    see e.g.
Mills
, at para. 24;
R. v. Mohamed, Islow and Miller
,
    2020 ONSC 5074, at paras. 44-51;
R. v. Gager
, 2012 ONSC 388, at paras.
    160-161, affd 2020 ONCA 274;
R. v. Monney
, 2017 ONSC 250, at paras.
    51-52;
R. v. Sappleton
, 2010 ONSC 5704, at paras. 157-158;
R. v.
    Sandham
, 2009 CanLII 59150 (Ont. Sup. Ct.), at paras. 15-17.

[50]

In its decision in
Phan
this court endorsed
    the following statement of Nordheimer J., as he then was, in
R. v. Skeete
,
    2012 ONSC 737, at para. 15, affd 2017 ONCA 926, 357 C.C.C. (3d) 159, leave to
    appeal refused, [2018] S.C.C.A. No. 508:

It remains the fact that a criminal trial is,
    after all, about the search for truth. A jury ought to be provided with
    information that will allow them to put the central facts into context
    including the nature of the relationships between persons connected to the
    events that might not otherwise be obvious. Jurors should not be placed in a
    situation where they are attempting to perform their truth seeking function in
    what is effectively either a factual vacuum or an artificial one.

This statement applies to the present
    case. Although the appellants are correct in saying that the core issue was
    credibility  whether Mr. Hayes evidence about what occurred would be believed
     the jury required information about how the gang operated, the motivations of
    gang members, and their internal discipline, to put his account into context.

[51]

Second, I disagree with the contention that the
    proposed expert evidence ought to have been excluded as unnecessary because Mr.
    Haye, who was a member of IDS, was testifying and could provide the required
    evidence. Coupled with this is the argument that the expert evidence was
    unnecessary because it would serve only to unfairly bolster Mr. Hayes
    evidence.

[52]

Given the scope and limitations of Mr. Hayes
    evidence, the trial judge properly rejected the argument that Detective
    Nassers evidence was unnecessary because Mr. Haye would provide all of the
    evidence needed to show that IDS was a street gang and that the accused were
    members of it. Mr. Haye had provided a police statement that was admitted as
    part of his evidence in chief on the Crowns motion, after a
voir dire
pursuant to s. 715.1 of the
Criminal Code.
He was acknowledged by
    everyone at trial to be a difficult witness  he was at times defiant or
    unresponsive. He was a
Vetrovec
witness whose account of the events
    had changed over time. The trial judges conclusion that Mr. Hayes testimony
    would not obviate the need for Detective Nassers evidence was informed by his
    understanding of the issues at trial, and his observations of Mr. Haye in the
    police interview that was the subject of the s. 715.1 application. He concluded:

Without the expert evidence, the jury will be
    left solely with the evidence of Dontay Haye. Dontay Haye may or may not give
    evidence regarding the use of violence by gangs to enforce discipline and
    communicate a message of obedience to the gang hierarchy.

Furthermore, Mr. Hayes evidence is
    problematic, to say the least. Mr. Hayes credibility will undoubtedly be
    subject to sustained assault in all respects. Without the context provided by
    the expert evidence, the jury will be left with his version of how gangs
    operate. The jury may well be left to puzzle over the purpose of an attempt to
    kidnap and beat Mr. Haye without context. The expert evidence will assist in
    evaluating his credibility (or lack of credibility).

[53]

The trial judges assessment of the limits of
    Mr. Hayes evidence was borne out at trial. Mr. Haye testified that he and the
    appellants and their co-accused were gang members. But he was unwilling to
    answer questions about IDS and how it operated. More importantly, his evidence
    did not provide the necessary context for the evaluation of the narrative.

[54]

Contrary to the argument advanced on appeal, the
    fact that Mr. Haye testified at trial did not preclude the Crown from calling
    expert evidence that was otherwise admissible.
Expert evidence
    respecting gangs can be relevant to understanding the context of the events and
    is not admissible only in cases where the victim is deceased or no gang member
    is testifying: see e.g.
Sandham
, at paras. 18-19;
Abbey
, at
    para. 4.

[55]

In
Boswell
a similar
argument was made and rejected  that expert
    evidence about a code of silence that may have caused a community member to lie
    to the police ought not to have been admitted because the same evidence was
    available from the alleged victim, Sharp. This court observed that while Sharp
    testified about the code and its effect on his conduct, his credibility was
    very much in issue, he was vigorously attacked by the defence, and his evidence
    was the subject of a strong
Vetrovec
warning. The court stated, In
    these circumstances it cannot be said that expert evidence regarding the
    general existence of a code of silence and its nature was unnecessary because
    the evidence was otherwise available through Sharp: at para. 31. In the
    present case, the trial judge made a similar evaluation in rejecting the
    argument that the evidence was unnecessary because it could have been provided
    by Mr. Haye.

[56]

Nor, as I will explain, do I accept the
    appellants argument that because the expert evidence provided context to
    understand the narrative that was provided mainly though the evidence of Mr.
    Haye, the expert evidence served only to unfairly bolster Mr. Hayes
    credibility.

[57]

The determination of a witnesss credibility and
    reliability is for the trier of fact and is not the proper subject of expert
    opinion. An expert opinion cannot be introduced if the purpose is solely to
    bolster a witnesss credibility (i.e.: oath-helping). Credibility is a
    notoriously difficult problem, and the experts opinion may be all too readily
    accepted by a frustrated jury as a convenient basis upon which to resolve its
    difficulties:
R. v. Marquard
, [1993] 4 S.C.R. 223, at p. 248.

[58]

Detective Nasser was not invited to express an
    opinion about the credibility of Mr. Haye, or about the events that were said
    to have occurred. And, while the credibility of Mr. Haye was assessed by the
    jury in the context of the evidence as a whole, including the opinion evidence
    of Detective Nasser, the purpose of Detective Nassers evidence was not to convey
    to the jury a belief that Mr. Haye was truthful. Rather, the purpose was to ensure
    that the jury evaluated all of the evidence in its proper context, to determine
    whether the alleged offences occurred, and if so, whether they were for the
    benefit of a criminal organization. While that context helped the jury to evaluate
    the credibility of Mr. Hayes account, evidence that may support the
    credibility of a witness does not, by reason of that incidental effect, offend
    the rule against oath-helping:
R. v. Llorenz
(2000), 145 C.C.C. (3d)
    535 (Ont. C.A.), at para. 28. See also
R. v. K.A.
(1999), 45 O.R. (3d)
    641 (C.A.), at p. 678 and
Sappleton
,

at para. 164.

[59]

In his final instructions, the trial judge explained
    to the jury the use they could make of the expert evidence, and he cautioned
    them against its misuse. He told the jury that it was necessary that they hear
    this evidence in relation to the offences relating to a criminal organization
    and for an understanding of how the gang works, and what its purpose was.
    Rather than inviting the jury to rely on the evidence to bolster Mr. Hayes
    credibility, he instructed the jury that [this evidence] will help you to place
    the evidence in context,
including why you must approach Dontay Hayes
    evidence with caution
.

[60]

For these reasons, I would not give effect to
    the appellants arguments respecting the necessity of the expert evidence.

(b)

Bias and partiality

[61]

The appellants argue on appeal that the trial
    judge erred in refusing to exclude Detective Nassers evidence because of
    serious concerns about his ability to be independent, impartial and unbiased. They
    rely on two incidents that arose in the context of the
voir dire
.
    First, Detective Nasser failed to disclose to the defence that he had spoken
    with a gang member and overheard the conversations of several gang members who
    attended court one day. This information only came out the next day when
    Detective Nasser was testifying, and Crown counsel asked about the encounter. According
    to the appellants, this information was significant as it would later form part
    of the trial judges ruling allowing Mr. Haye to testify via CCTV. Second, Detective
    Nasser was unwilling to answer questions from defence counsel outside of court.
    The appellants also point to Detective Nassers CV, where, in listing his
    experience as a gang expert, under one trial where he had been previously
    qualified, he noted that both accused were convicted. This implies that Detective
    Nasser was proud of the fact that there had been a conviction in a case where
    he had testified for the Crown, and demonstrated that he was not impartial.

[62]

In their appeal, the appellants assert that
    Detective Nassers evidence did not meet the initial stage of the
Mohan
test because these incidents were inconsistent with the experts duty to the
    court to be an independent witness. They also argue that the experts bias was
    not considered by the trial judge at the cost/benefit stage of determining
    admissibility.

[63]

The Crown contends that the three concerns
    raised by the appellant did not undermine Detective Nassers impartiality to
    the point where his evidence ought to have been excluded. First, the encounter
    with gang members that Detective Nasser failed to disclose to the defence had
    no bearing on his report and the trial judge had determined that the appropriate
    remedy would be for Detective Nasser to disclose his notes, if any, before
    cross-examination by the defence. Second, Detective Nasser had explained that
    his reluctance to answer a question from defence outside the court was because
    of his prior experience with counsel using the opportunity to decide whether to
    use the question in their cross-examination and that he felt it was most fair
    to answer the question in court. The trial judge addressed this in his reasons
    and concluded that the evidence was still reliable. Third, the CV entry is a
    factual statement of the outcome of that trial and Detective Nasser had listed
    that an accused had been acquitted in a different entry. The Crown also points
    out that defence counsels submissions at trial concerning bias and partiality were
    quite different from those now raised on appeal.

[64]

Impartiality and lack of bias are part of the
    threshold requirements for admissibility, in determining whether an expert is
    properly qualified. Exclusion at the threshold stage should occur only in very
    clear cases, where the proposed expert is unable or unwilling to provide the
    court with fair, objective and non‑partisan evidence. Alleged partiality
    and bias are considered again at the gatekeeping stage in weighing probative
    value (which includes relevance, necessity, reliability and absence of bias)
    against the dangers associated with expert evidence. Context is important; both
    the extent of the experts alleged bias and the nature of the proposed evidence
    are relevant:
White Burgess
, at paras. 49, 53-54;
R. v.
    Natsis
, 2018 ONCA 425, 140 O.R. (3d) 721, at para. 11;
Mills
, at
    para. 45.

[65]

While the issue of bias and partiality was raised
    by defence counsel at trial, as the Crown points out, defence counsels
    arguments differed from what is advanced on appeal. At trial, defence counsel
    did not raise concerns about Detective Nassers CV, take issue with his failure
    to disclose his encounter with gang members after this matter was raised and
    remedied by the trial judge, nor suggest his evidence was inadmissible at the
    first stage of
Mohan
on the basis that he was unwilling or unable to
    meet his obligations as an impartial and unbiased expert. Rather, in making submissions
    about the probative value versus prejudicial effect of the evidence, defence
    counsel asserted that Detective Nasser was not a disinterested expert because (1)
    he did not wish to engage with defence counsel on a particular issue outside
    the courtroom setting; and (2) his background work into certain incidents of
    gang association or indicia of gang membership involving the accused did not go
    far enough. In addressing these arguments, the trial judge concluded:

It is true that some of [Detective] Nassers background
    work could have gone further. It is also true that he should have been prepared
    to answer counsels questions outside of court. It is usual that police
    officers, and not only experts, do that. I found it troubling that he did not
    do so. Nonetheless, I am satisfied that his evidence meets the test for
    threshold reliability. The issues raised by counsel go to the weight to be
    given to his opinion by the jury.

[66]

Leaving aside the fact that this argument was not
    raised at first instance, there is no error in the trial judges refusal to
    exclude Detective Nassers expert evidence at the threshold stage due to bias
    or partiality. The concerns raised by the appellants did not demonstrate a
    clear unwillingness or inability for Detective Nasser to meet his obligations
    as an expert witness. Moreover, the appellants accepted that Detective Nasser
    was a properly qualified expert.

[67]

The appellants submitted in argument on the
    appeal that, contrary to what I have expressed above, the trial judge
    considered partiality only at the first stage of
Mohan
, and not at the
    second stage of weighing prejudice. They point to the statement in his reasons
    that he was satisfied that [the experts] evidence meets the test for
    threshold reliability. The issues raised by counsel go to the weight to be
    given to his opinion by the jury.

[68]

I disagree. Although, in this passage, the trial
    judge referred to threshold reliability, it is apparent from the structure of
    his reasons (where this paragraph followed a discussion of the principles applicable
    to the cost/benefit analysis), as well as the submissions of counsel at trial,
    that he did what he was invited to do. He addressed the argument that the incidents
    of alleged partiality affected the probative value of Detective Nassers
    evidence. He had already determined that the evidence met the threshold tests
    for relevance and necessity and the two other
Mohan
criteria had been
    conceded, including that Detective Nasser was a qualified expert. The trial
    judge was concerned by Detective Nassers refusal to engage with defence
    counsel outside the court room and the extent of his background work, but he concluded
    that this did not reduce the probative value in the cost/benefit analysis such
    that his evidence should be excluded. The trial judge properly observed that
    the issues raised by the defence could be addressed in the experts
    cross-examination.

[69]

The trial judge did not err in his approach to
    the appellants arguments about bias and partiality. There was no realistic
    concern that the expert was unable to comply with the duty to provide
    independent, impartial and unbiased evidence. Nor did the trial judge err in
    his assessment of these factors as part of the cost/benefit analysis. As in
Mills
,
    at para. 68, the trial judge heard the expert testify in the
voir dire
,
    had his report, and was therefore in a good position to determine whether [the
    expert] showed partiality, a lack of independence, and/or bias.

(3)

Did the trial judge err in his cost/benefit
    assessment of the proposed expert evidence?

[70]

The appellants argue that, even if Detective
    Nassers evidence was necessary and reliable, the prejudicial effect of the
    evidence outweighed its probative value. The probative value of the expert
    evidence was low because Mr. Haye was available to testify and did testify
    about gang-related information. The prejudicial effect, by contrast, was
    significant because Detective Nassers evidence was bad character evidence. The
    evidence regarding gang culture portrayed a lifestyle of crime and violence,
    and by implication painted the accused as stereotypical thugs.

[71]

Similar to their argument at the initial stage
    of the admissibility test, concerning necessity, the appellants contend that
    the effect of introducing this evidence was simply to bolster Mr. Hayes
    credibility by giving the jury the impression that Mr. Haye was telling the
    truth because [the three accused] were gang members and gang members are bad
    people. The appellants say that Mr. Hayes evidence was enhanced by
    dragging the characters of the appellants through the mud. They say this was
    particularly important with respect to the charge of attempted murder: while
    the allegations as a whole were supported by video evidence, the only evidence
    with respect to the attempted murder, that Mr. Oppong told Mr. Haye he
    would kill him if he did not give up the gun, came from Mr. Haye himself. The
    appellants argue that the jury undoubtedly would have been influenced by the
    expert evidence in assessing the credibility of this allegation.

[72]

The Crown submits that there was no error in the
    trial judges conclusion that the probative value of the evidence outweighed
    its prejudicial effect. Detective Nasser provided limited opinion evidence and
    limited information about the appellants. The appellants admitted that they
    were members of IDS. The jury was also properly instructed on the use of this
    evidence.

[73]

The weighing of the costs and benefits of proposed
    expert evidence is entitled to deference. Doherty J.A. in
Abbey
, noted
    that the gatekeeper phase is more difficult and subtle, involves the exercise
    of judicial discretion and is case‑specific. He observed, at para. 79,
    that [d]ifferent trial judges, properly applying the relevant principles in
    the exercise of their discretion, could in some situations come to different
    conclusions on admissibility.

[74]

There was no reversible error in the trial
    judges assessment of the costs and benefits of receiving the expert evidence.

[75]

First, as I already have observed, the trial
    judge considered the allegations of partiality as part of his assessment of the
    reliability of the evidence, in weighing its probative value against its
    prejudicial effect. Reliability includes consideration of the extent to which
    the expert is shown to be impartial and objective:
Abbey
, at para. 87;
Mills
, at para. 45.

[76]

Second, and as I have explained, there was significant
    probative value to the expert evidence in helping the jury to understand the
    context of what occurred. The central issue for the jury to determine was
    whether Mr. Haye was telling the truth about what happened. He was thoroughly
    cross-examined. It was brought home to the jury that it was their
    responsibility, as the finders of fact, to determine Mr. Hayes credibility and
    reliability. The role of the expert evidence was to help them to understand the
    context in which Mr. Haye and the three accused were operating.

[77]

Third, and contrary to Mr. Oppongs submissions
    on appeal, there is no indication that the jury would have improperly used the
    expert evidence to reason that, as a member of a gang he was a bad person, and
    that accordingly Mr. Haye must have been telling the truth. Mr. Haye himself
    was an admitted gang member who sometimes carried a gun and sold drugs. The
    jury was specifically cautioned, repeatedly, not to engage in propensity
    reasoning. They were also cautioned about the dangers of relying on Mr. Hayes
    evidence, and instructed that the expert evidence was to help them to place the
    evidence in context, including why they must approach Mr. Hayes evidence with
    caution. Jurors are presumed to understand and follow the instructions they are
    given:
R. v. Bains
, 2015 ONCA 677, 127 O.R. (3d) 545, at paras. 61,
    98, leave to appeal refused, [2015] S.C.C.A. No. 478. Finally, the jury clearly
    did not accept Mr. Hayes evidence without reservation: they were not satisfied
    that Mr. Oppong threatened to kill Mr. Haye, as they found him not guilty of
    attempted murder.

[78]

For these reasons I would dismiss this ground of
    appeal.

(4)

Did the trial judge err in refusing to
    reconsider his ruling based on a material change in circumstances?

[79]

The appellants assert that the fact that they
    were prepared to admit that IDS was a gang and that they were members of IDS
    constituted a material change in circumstances. They submit that the Crown
    opposed the application and refused to consent to the admission, which was an
    improper attempt to keep an issue artificially alive to introduce prejudicial
    evidence. Because the appellants were willing to admit almost all of what the
    expert would testify about, the prejudicial effect of the evidence would outweigh
    its probative value, which was almost nil. They contend that the trial judge
    erred in concluding that there was no material change in circumstances, and
    then refusing to reconsider his ruling. The appellants also asserted in oral
    argument, that the trial judge ought to have required the Crown to work with
    defence counsel to come up with a set of agreed facts, and then to consider
    whether the expert evidence was admissible in light of the new evidentiary
    framework.

[80]

The Crown submits that there was no error in the
    trial judges ruling on the application to re-open the ruling. While trial
    judges can revisit evidentiary rulings, the defence had the onus of
    establishing a material change in circumstances. The Crown asserts that the trial
    judge did not err in concluding that the appellants proposed admissions did
    not constitute a material change in circumstances, as those admissions would
    not assist the jury in understanding the context of Mr. Hayes evidence.
    Further, there would be difficulties in managing a trial where one of the
    accused would not make the same admissions as the other two, and the Crown was
    not willing to use an agreed statement of facts as the necessary context cannot
    be provided to the jury in a list of facts.

[81]

The point of departure is that a defendants
    admission requires the acceptance of the Crown:
Criminal Code
,
s. 655;
Castellani v. R.
,
    [1970] S.C.R. 310. That said, while a trial judge cannot require the Crown to
    accept certain admissions, the Crown should not be allowed to gain entry for
    prejudicial evidence by refusing to accept the admissions [an accused is
    prepared to make]:
R. v. Proctor
(1992), 69 C.C.C. (3d) 436 (Man.
    C.A.).

[82]

The issue here was not whether or not the Crown
    was prepared to accept the admissions the accused were willing to make, or
    whether the trial judge had the ability to revisit his ruling in the light of admissions
    that were
proposed
, even if not yet accepted by the Crown. Rather, the
    focus was on the extent of the proposed admissions, and whether they would
    affect the cost/benefit analysis in relation to the expert evidence.

[83]

The appellants were prepared to admit that IDS
    existed, that they were members and that if the jury found that the acts were
    committed, that it was at the behest of a criminal organization. The third
    accused, Mr. Thomas-Stewart, however was only prepared to admit that IDS is a
    street gang, that association with other members is one of the characteristics
    of a gang member, and his associations on four separate dates (that did not include
    the date of the alleged offences). He was not prepared to admit that he was a
    member of IDS or that, if the allegations of his conduct were proven, it was
    for the benefit of a criminal organization.

[84]

The appellants assert that the trial judge was
    wrong to conclude that there was no material change in circumstances in this
    case. In oral argument, the appellants also argued that the trial judge did not
    even embark on an analysis of the effect of the proposed admissions because he
    concluded that there was no change in circumstances.

[85]

I disagree. The trial judge accepted that there
    was a change in circumstances, but he concluded that it was not
material
.
He accepted that he had the ability to revisit his ruling, and he heard
    argument on the issue. The trial judge properly observed that, in order for the
    change of circumstances to be material, it must alter the balance between the
    prejudicial effect and probative value of the evidence. The defence argument
    was that the proposed admissions would render the expert evidence much less
    probative because they were more extensive than the expert evidence. The trial
    judge properly rejected this submission. While the proposed admissions would
    obviate the need for certain evidence in relation to the appellants membership
    in IDS, the trial judge observed that [t]he key point about [Detective]
    Nassers evidence is that it is supposed to help the jury understand the
    background. The proposed admissions do nothing to advance the jurys
    understanding without context. In other words, the trial judge concluded that
    the changed circumstances  the proposed admissions by the accused  were not
    material because they did not alter the cost/benefit analysis in relation to
    the expert evidence.

[86]

Mr. Thomass counsel argued before the trial
    judge that the Crown was attempting to keep the issue of how gangs operate
    artificially alive in order to bolster Hayes credibility. Rejecting the submission
    of Mr. Thomass counsel that the expert evidence was simply an attempt at
    oath-helping, the trial judge noted: As I stated in my original ruling, the
    purpose of the expert evidence was to allow the jury to understand his evidence
    given the circumstances of a gang-related offence.

[87]

As I have already explained, permitting the
    expert to testify in order to provide context for the assessment of the
    narrative, including the account provided by Mr. Haye, was a proper purpose for
    the admission of the expert evidence in this case. The trial judge had already
    made this determination. The jury was not invited to use the evidence to
    bolster Mr. Hayes credibility, nor was there a reasonable prospect that they
    would misuse the evidence.

[88]

There were arguments at trial about the scope of
    Detective Nassers evidence in light of the proposed admissions, which were not
    renewed on appeal. As I have already noted, in the course of Detective Nassers
    evidence, counsel for the appellants conceded their clients membership in IDS
    which resulted in the Crown refraining from eliciting certain evidence from
    Detective Nasser regarding their associations.

[89]

Finally, on appeal the appellants contend that
    the trial judge should have required the parties to attempt to agree to facts
    about general characteristics of gangs, that could have been entered as an
    agreed statement of facts. Counsel did not suggest how that could have been
    done in this case  that is, what facts could reasonably have been admitted. The
    record suggests that there may have been some discussions between defence
    counsel and the Crown that had not borne fruit, and that Mr. Oppongs counsel suggested
    in the application to revisit the expert evidence ruling that this could be
    done. There had already been a lengthy
voir dire
to determine the
    admissibility and scope of the experts evidence in this case. There is no
    indication that anyone had proposed to the trial judge, in advance of his
    initial ruling, that the expert evidence could or should have been introduced
    through an agreed statement of facts. This submission, made late in the day by
    one defence counsel, attracted the appropriate response from the trial judge.
    He observed that there was no agreed statement of facts and that he had no
    power to compel any party to make a concession it was not otherwise prepared to
    make.

[90]

For these reasons I see no error in the trial judges
    refusal to exclude Detective Nassers expert evidence on the defence motion to
    revisit his ruling.

III

THE SENTENCE APPEAL

[91]

Mr. Oppong appeals his sentence. He says that
    the trial judge erred in making a finding of fact that was unsupported by the
    evidence  that he was the leader of the IDS. The trial judge stated that the
    most important aggravating factors for Mr. Oppong included his leadership of
    IDS. Mr. Oppong submits that there was no evidence to support this conclusion,
    and that this error led the trial judge to impose a longer sentence on the
    appellant than on his two co-accused.

[92]

The Crown argues that the trial judges
    conclusion that Mr. Oppong had a leadership role in the gang was supported by
    the evidence, and that in any event the trial judge explained why he should
    receive a greater sentence than his co‑accused, and imposed a sentence that
    was fit in all the circumstances.

[93]

Although I would grant leave to appeal sentence,
    I would dismiss the sentence appeal.

[94]

First, there was evidence to support the trial
    judges reference to Mr. Oppongs leadership role in the gang. He was
    described by Mr. Haye as one of the older heads of the gang. Mr. Oppong is
    correct in noting that there was evidence about the leadership, including Detective
    Nassers list of the ten leaders (which did not include Mr. Oppong). The trial judge
    did not conclude however that Mr. Oppong was the leader of IDS, only that he
    had a leadership role.

[95]

More importantly, however, it was open to the
    trial judge to find, as he did, that Mr. Oppong took the lead role in the
    kidnapping of Mr. Haye, which Mr. Oppong had admitted was for the benefit
    of IDS. In fixing the appropriate sentences, the trial judge considered the
    specific role each of the accused had played in the attack on Mr. Haye. He
    concluded that Mr. Oppong had played the lead role in the kidnapping and was enforcing
    the rules of the gang. This was in contrast to his co-accused who had
    secondary roles.

[96]

An appellate court can only interfere with a
    sentence when there is a demonstrated error of law or principle that had an
    impact on the sentence, or the sentence is demonstrably unfit:
R. v.
    Friesen
, 2020 SCC 9, 391 C.C.C. (3d) 309, at para. 26. No error has been
    demonstrated. Mr. Oppongs sentence was fit. There is no basis for appellate
    intervention.


IV

DISPOSITION

[97]

For these reasons I would dismiss the conviction
    appeals, and while I would grant leave to Mr. Oppong to appeal his sentence, I
    would dismiss his sentence appeal.

Released: May
    25, 2021 P.R.

K.
    van Rensburg J.A.

I
    agree. Paul Rouleau J.A.

I
    agree. B.W. Miller J.A.





[1]

In
    his factum, Mr. Oppong also challenged the order under s. 743.6(1.2) of the
Criminal Code

requiring him to serve one half of his sentence before
    he is eligible to apply for parole. This issue, which is fully answered by the
    Crowns factum, was not pursued in oral argument, and will not be addressed in
    these reasons.



[2]

Detective
    Nasser was referred to in the reasons below as Sergeant Nasser, the position
    he held when he prepared his expert report.


