Massereene murder trial: DNA does not tell full story, court is told
DNA evidence cannot establish all the circumstances in the case against two men accused of murdering two soldiers, a court heard today.
Ohio professor Dan Krane also expressed concern about the small size of the sample used in the trial of Colin Duffy.
Brian Shivers and Duffy deny the murder of Sappers Mark Quinsey and Patrick Azimkar, who were shot outside their army base in Antrim.
Professor Krane said: "What it establishes is that his DNA may be associated with the glove and it may be associated with the belt buckle of the car.
"The presence of a DNA profile per se does not say anything about the timeframe or the circumstances under which the DNA came to be there.
"The DNA tests themselves cannot answer that type of question.
"That is left more to a court or a jury to decide what those circumstances and timeframe (are). The DNA tests can simply tell us that DNA was found on those items."
Sappers Quinsey, 23, and Azimkar, 21, were shot dead by the Real IRA as they collected pizzas with comrades outside Massereene Army base in Antrim town in March 2009.
Duffy, 44, from Forest Glade in Lurgan, Co Armagh, and Shivers, 46, from Sperrin Mews, in Magherafelt, Co Derry, deny two charges of murder and the attempted murder of six others - three soldiers, two pizza delivery drivers and a security guard.
Professor Krane told Belfast Crown Court sitting in Antrim that the sample relating to Duffy came from a mixture of DNA from two or more people, meaning there was a possibility that somebody other than Duffy came into contact with the glove.
He said Dr Mark Perlin, a prosecution witness who used an innovative DNA analysis method to link the accused to the getaway car, did not have a proper understanding of certain effects associated with the research.
Prosecution barrister Terence Mooney QC said the witness had opposed efforts to advance the use of DNA analysis.
"As soon as you lose the battle on an issue you move to another one and create more confusion," he said.
"Throughout your career in giving evidence in forensic cases you have tried to build up impediments to the advance of DNA being used in court."
Professor Krane disagreed.
The trial continues.