THE man accused of killing Elaine Doyle willingly volunteered a sample of DNA to detectives investigating her murder — and it matched DNA found at the crime scene.

The High Court in Edinburgh heard yesterday how police in Greenock set up Operation Evergreen to continue the hunt for the Elaine’s killer.

They tried to visit every male who had come to the attention of police since her death in June 1986 — which included the now-accused in the case, 49-year-old John Docherty.

The men were asked for ‘elimination samples’ which would be destroyed at the end of any court case and would not find their way on to the national database.

Detective Constable Stuart Young, 49, told how a visit to Docherty’s 1986 address in May 2012 found his ex-sister-in-law living there.

She was able to give them an up-to-date address for him in Trafalgar Street.

Mr Young said he and a colleague found Docherty there and he willingly gave a DNA sample, fingerprints and allowed himself to be photographed.

The detective said Docherty signed a form agreeing: ‘I have been made aware I am not obliged to provide this sample and that any information from this sample may be used in evidence.’ Docherty’s defence QC, Donald Findlay asked DC Young: “He happily consented, immediately and without demur?” The officer replied: “Absolutely.” Fiona McMahon, 42, who heads the specialist DNA database team at the Scottish Police Authority lab in Dundee, said the sample from Docherty was one of 361 processed in her lab.

She told the High Court in Edinburgh she compared it with what was tagged ‘the crime scene profile’.

Ms McMahon said: “It was a full match.” The expert told the trial she had also examined elimination samples provided by some of the possible suspects put forward by Docherty’s defence team, but found no matches.

The jury also heard yesterday that Docherty was living in Greenock in 1986 but spent some time in the Army, before moving back to the town.

He denies murder and claims that at the time he is alleged to have stripped and strangled Elaine he was at home with his parents, who are no longer alive.

Docherty has pleaded not guilty and his defence team have lodged a special defence of incrimination of 41 others.

The trial continues.