A forensic scientist’s conclusions in the case of a man accused of murdering two teenage girls 37 years ago are “misguided, unjustified and positively misleading”, a court has heard.
Angus Sinclair, 69, denies raping and murdering Christine Eadie and Helen Scott, both 17, who were last seen at the World’s End pub in Edinburgh on October 15 1977.
He is accused of carrying out the attacks along with his brother-in-law, Gordon Hamilton, who is now dead.
The High Court in Livingston has heard six days of evidence from forensic scientist Geraldine Davidson, who works with the England-based company Cellmark.
Ms Davidson has talked the jury through DNA samples taken from items of clothing that were used as ligatures to bind and strangle the girls.
She told the court analysis of one of these - the belt from Helen’s raincoat that was found around her wrists - suggested the two girls may have still been together when the ligature was tied.
But defence QC Ian Duguid said forensic scientists had prepared a report for the defence that did not agree with that conclusion.
He said: “You are making a conclusion which is misguided, unjustified and positively misleading.”
Ms Davidson replied: “I appreciate that’s their interpretation of these findings.”
She added: “I don’t agree and stand by my interpretation of the findings.”
The jury has heard a defence report detailing Sinclair’s version of events, in which he claims he and Hamilton had consensual sexual intercourse with both girls in a vehicle in Holyrood Park, after which Sinclair left to go fishing.
He claims the girls were ‘’alive and unharmed’’ when he left their company, and he has lodged three special defences of consent, alibi and incrimination.
Mr Duguid said: “There are three different circumstances to consider. One of them is that some consensual sexual activity had taken place between Mr Sinclair and both of the girls.
“Two, that Mr Sinclair wasn’t there when the girls were killed, and three, he is blaming a named individual Gordon Hamilton for the killing of the two girls.”
Ms Davidson told the court her report had been written before that information was made available.
It concluded that Sinclair had been in contact with “most if not all” of the ligatures in the case.
Mr Duguid suggested Hamilton could have been the person who transferred Sinclair’s DNA on to the pieces of clothing used as ligatures.
He said: “Leaving aside the belt section of Christine Eadie’s ligature, am I right that every single one of the samples taken across the ligatures had Gordon Hamilton as either the major or most prominent contributor?”
The witness replied: “Largely speaking, yes.”
She added: “We know they had been together. The potential for one to transfer the other person’s DNA is a viable option.”
Mr Duguid continued: “So every single site could have been Gordon Hamilton transferring Angus Sinclair’s DNA by a secondary transfer?”
“It could have, yes,” she replied.