Wing Fu Cheung, also known as Nelson Cheung, was stabbed to death after his car was forced off the road outside Randalstown in January 2015.
The 65-year-old Ballymena man ran the Double Value Chinese takeaway restaurant in Randalstown.
Gary Thompson, 34, pleaded guilty to three charges lat Belfast Crown Court.
He was previously accused of Mr Cheung's murder, but that charge was left on the books.
Gary and Lisa Thompson had been due to stand trial and a jury was sworn in yesterday, but they were re-arraigned today.
Both were released on continuing bail, to be sentenced at a later date.
Gary Thompson, formerly of Cunningham Way in Antrim, admitted robbing Mr Cheung's wife, Kam-Fung Cheung, also known as Winnie.
He also pleaded guilty to assisting offenders by allowing two men who have admitted the murder - Virgilio Augusto Fernando Correia and Christopher David Menaul - to take refuge in his home, as well as letting them remove clothing and clean themselves after the killing.
Thompson also admitted perverting the course of justice by threatening Correia in an attempt to stop him talking to the police.
Lisa Thompson, 34, from Erskine Park in Ballyclare, admitted assisting offenders, handling stolen goods and perverting the course of justice.
The offences happened between 6 and 9 January 2015.
Last month, 35-year-old Correia admitted killing Mr Cheung, wounding his wife with intent to do her grievous bodily harm, and robbing her.
In November, 25-year-old Menaul pleaded guilty to the same three charges.
Both men are in custody, on remand, awaiting sentence.

Jon Platt was given a fine of £120 when he took his daughter away for a week.
But he refused to pay and the High Court found in his favour that this holiday absence did not constitute regularly missing school.
But the government insists children should not miss lessons in term-time.
The Supreme Court will now rule on a case which has raised questions of parents' rights and responsibilities.
It also prompted a debate about higher travel costs during school holidays - with complaints from parents about price hikes.
It comes as a survey shows rising numbers of parents being prosecuted after their children missed school.
A Press Association survey found there were almost 20,000 prosecutions in 2015, up more than 20% on the previous year, leading to more than 11,000 fines and in eight cases, jail sentences.
The case being considered by Supreme Court judges centres on a week's holiday to Disney World in Florida two years ago - when Jon Platt took his daughter away from her school on the Isle of Wight without the head teacher's permission.
Mr Platt was fined £60 which with non-payment was increased to £120 - after which he faced prosecution for failing to ensure his daughter's regular attendance at school.
But his defence has been that a week's absence in term-time should not be seen in isolation - and that when it was considered in the context of his daughter's overall attendance of over 92%, she could not be said to have regularly missed school.
When the case came before magistrates on the Isle of Wight, they ruled that there was no case to answer, as Mr Platt's daughter had attended school regularly.
Truancy prosecutions in England in 2015
Source: PA
When this was put to appeal, the High Court accepted that magistrates had been entitled to consider school attendance outside of the week of the term-time absence.
The Department for Education, which has been trying to reduce truancy and improve attendance, has supported the Isle of Wight council in challenging the rulings.
And when the case was heard at the Supreme Court earlier this year, the local authority argued that an unauthorised absence "for even a single day, or even half a day" could be unlawful.
But Mr Platt's representatives argued that it was unacceptable to interpret the rules in a way that would criminalise so many parents.
Ministers argue that allowing parents to take children out of school in term-time is disruptive to their learning and caused problems for teachers and the rest of the class when pupils returned and had to be helped to catch up.
A Department for Education spokeswoman said: "Our position remains that children should not be taken out of school without good reason.
"That is why we have tightened the rules and are supporting schools and local authorities to use their powers to tackle unauthorised absence."
A county Antrim husband and wife have admitted helping the murderers of a Chinese restaurant owner try to cover up their crime.
[NEXT_CONCEPT]
A father who is challenging a fine for taking his daughter on an unauthorised term-time holiday will find out from the Supreme Court whether he has won or lost his long legal battle.