A DNA analysis technique used to link two men to the murders of two British soldiers has never once been admitted as evidence in a UK or Irish court, their trial has heard.
The statistical computer based model which connected the defendants to genetic samples found in the getaway car driven by the killers of English Sappers Mark Quinsey and Patrick Azimkar is also not yet trusted by the broad scientific community, one of the accused's lawyers told Antrim Crown Court.
But the inventor of the system which linked Colin Duffy and Brian Shivers to the vehicle robustly defended its reliability and insisted it provided more accurate results than traditional DNA analysis.
Returning to the witness stand for a second day, Dr Mark Perlin, an American-based academic, also denied claims from the defence that he had a financial motive for the data produced by his patented technique being accepted by the court.
Judge Mr Justice Anthony Hart, who is sitting without a jury, had been hearing Dr Perlin's evidence before making a ruling on a defence application for it to be excluded from his final deliberations.
Sappers Quinsey, 23, and Azimkar, 21, were shot dead by the Real IRA as they collected pizzas with colleagues outside Massereene Army base in Antrim town in March 2009.
Duffy, 43, from Forest Glade in Lurgan, Co Armagh, and Shivers, 46, from Sperrin Mews in Magherafelt, Co Londonderry, deny two charges of murder and the attempted murder of six others - three soldiers, two pizza delivery drivers and a security guard.
Dr Perlin revealed the results of tests he carried out on data from a seat belt buckle and a mobile phone found inside the Vauxhall Cavalier getaway car, which was abandoned partially burnt out on a country road just a few miles from the shootings. He said that a DNA sample found on the buckle was 5.91 trillion times more likely to be Duffy's than someone else's while a sample from inside the phone was 6.01 billion times more likely to belong to Shivers than another person.
The defendants' lawyers vigorously challenged Dr Perlin under cross-examination. Barry McDonald QC, representing Duffy, claimed the expert's "True Allele" system was still a "work in progress" and had not yet been subjected to enough validation to deem it reliable.
But Dr Perlin insisted the system had been rigorously validated - something he said had not been done with traditional methods.