Gareth O'Connor murder: Letter was Hallett 'error 2'
An independent review of the government's On the Runs scheme, commissioned after the trial of 1982 IRA Hyde Park bombing suspect John Downey collapsed, identified two further unnamed individuals who had potentially been sent letters of assurance in error.
It emerged on Monday that the letter referred to in Lady Justice Hallett's report last July as "error 2" had been sent to a suspect in the Gareth O'Connor murder case.
Mr O'Connor was 24 when he disappeared in May 2003.
He had been on his way to Dundalk Garda Station to sign as part of his bail conditions after being charged with membership of the Real IRA. Two years later, a car containing his body was dragged from Newry Canal.
Under the On the Runs letter scheme, set up in 2007 as part of the Northern Ireland peace process, more than 200 people were told they were not wanted for paramilitary crimes committed before the 1998 Good Friday Agreement.
The judge said the agreement had created potential anomalies, as it did "not appear to have been envisaged that offences committed after 10 April 1998 would be considered by the RUC or the PSNI when reviewing the status of individuals".
Her report said Operation Rapid - the PSNI team tasked with assessing the OTR cases - had reviewed an individual "linked to two terrorism offences in the 1970s, as well as serious offences in 2003".
A letter from Det Ch Supt Norman Baxter to ACC Peter Sheridan made a "somewhat ambiguous reference to the 2003 offence", but then stated there was no basis to seek the person's arrest for any offence prior to the 1998 Good Friday Agreement, the report said.
The judge said a subsequent letter signed by ACC Sheridan to the Public Prosecution Service "did not contain the caveat in relation to the agreement and simply stated, 'enquiries indicate that XXXX is not currently wanted by PSNI'."
When the letter was sent from the PSNI to the office of the DPP, it included the wording: "On the basis of the information currently available, there is no outstanding direction for prosecution in Northern Ireland, there are no warrants in existence nor are you wanted in Northern Ireland for arrest, questioning or charge by the police".
Lady Justice Hallett said: "In my view, a letter of assurance without a time limitation should not have been sent by the NIO in this case.
"However, having failed to identify the potential for error arising out of the discrepancy between the PSNI terms of reference and the letters of assurance being sent, the NIO were not to know about the 2003 offence."
She said the case highlighted another shortcoming in the scheme's operation, as when the PSNI decided that an individual was not wanted for any pre-1998 offence, these warnings were routinely removed from police computers.
"In this case the 'wanted' warning for the 2003 offence was removed in 2007 - the same point at which the warning relating to the offences in the 1970s was removed.
"Allowing for the possibility that this might be coincidental, I should make it clear that the PSNI is aware of the circumstances of this case."