Ronnie Coulter, 48, was convicted earlier this month of stabbing to death Mr Chhokar in Overtown, North Lanarkshire in 1998. He is due to be sentenced next week.
He was initially cleared following a trial in 1999, but the Crown applied to have his acquittal set aside under double jeopardy laws.
In a newly published judgement, Scotland’s most senior judge, Lord Carloway, said an admission Coulter had made to his sister about carrying out the murder had helped provide a “strong basis” for setting aside the acquittal.
According to the court’s published opinion, the Crown had brought forward new evidence that Coulter admitted his crime to his sister, Margaret Chisholm, after his acquittal.
Coulter was also said to have told his brother-in-law he had “got away with it”, while Katelyn Finlay, whose mother had been in a relationship with Coulter, said he had told her mother: “Aye, I done it”.
Coulter was also said to have asked his sister to find a knife which had been deposited somewhere between Overtown and Gowkthrapple and to buy a set of knives and put the smallest one in a drawer in his flat in the hope of setting up “a situation in which the police would discover a knife, which might have been used to commit the murder but which was not capable of being forensically linked to him”.
Lord Carloway said: “What happened after the acquittal, if Mrs Chisholm is to be accepted, is that there emerged evidence that [Coulter] had already filled what might have been regarded as the major fissure in the Crown case.
“He had admitted that he had been the one who had stabbed the deceased.”
Lord Carloway said Coulter had made statements to others, but the “clearest incriminating statement” was to Mrs Chisholm.
“It is she, [Coulter’s] sister, who also provides the new evidence concerning the elaborate attempt at knife recovery and planting. As [Coulter] recognised, it is a short step to holding that this evidence strengthens substantially the ‘case’, that is to say the evidence at the original trial, against the first respondent.”
Coulter was convicted by a majority verdict.