DNA matching that of the man accused of strangling Elaine Doyle was found on her naked body, but not on her clothes.
Forensic scientist Pauline McSorley told a trial on the 28th anniversary of the Greenock teenager's death, it was more than a billion times more likely that the DNA profile she found came from John Docherty than from any other unrelated male.
She agreed that sweat or droplets of saliva deposited as a perpetrator strangled the 16-year-old girl could account for her findings. Mrs McSorley, 57, described years of work on samples taken from the crime scene.
She and her colleagues examined tape which had been laid across Ms Doyle's body in the hope of trapping hairs or fibres which might help track down her killer.
The forensic scientists also tested the teenager's clothes for clues.
The High Court in Edinburgh heard yesterday how some tiny traces matched the DNA of police who had handled clothing or the body, forensic scientists, and a member of the laboratory staff. But two results could not be accounted for until Mr Docherty volunteered a sample of his DNA in May 2012 and gave another sample on March last year, when he was arrested and charged with the murder.
The trial heard that the DNA on Ms Doyle's back was an exact match.
DNA on the girl's face also matched Mr Docherty's profile. Mrs McSorley said it was 560,000 times more likely it came from the accused than any other unrelated male.
She told the trial that if the male DNA on Ms Doyle's back had got there as she socialised at a disco in Greenock's Celtic Club or later in the town centre, she would have expected to recover DNA from the blouse, but didn't.
Mr Docherty, 49, now of Hunters' Quay, Holiday Village, Dunoon, denies murder. He claims at the time he is alleged to have stripped and strangled Elaine Doyle, 16, he was with his parents,who are no longer alive, at their home in Anne Street.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereComments are closed on this article