Questions raised by Brian Shivers' case 3 May 2013 Last updated at 17:38 By Vincent Kearney BBC NI home affairs correspondent The police could not believe their luck when the car used by the gunmen who killed two soldiers and wounded three others and two pizza delivery men was found intact seven miles from the scene of the attack. They had tried to burn the Vauxhall Cavalier, but failed. The police described the vehicle as a potential treasure trove of evidence. DNA found on matchsticks and a mobile phone inside the car formed the foundation of the case against Brian Shivers, and the decision by the judge in his first trial to find him guilty of murder. Mr Shivers had said as part of his defence that two men who had been in his house could have left traces of DNA on the matches. In the first trial a forensic expert called by the prosecution said this was not the case. Asked if either of the men could have contributed to the DNA profile obtained from the matchsticks, the scientist replied - "No, they could not." The judge, Mr Justice Harte, said he accepted there was "no scientific evidence whatever" to show that the two men named "could have contributed to the DNA from these matchsticks." Forensic expert In the first trial, this forensic evidence was given significant weight. But a different picture emerged during the retrial when another forensic scientist provided a different conclusion. The expert witness told the court he was unable to exclude one of the men named by Brian Shivers as a source of DNA. The court was also told that up to four other DNA profiles, other than that of Brian Shivers, were found on items recovered from the getaway car. Police experts also conceded that the evidence may have been contaminated. During cross examination, forensics officers revealed that the back of the seat of the car had been folded down on top of the two matches found inside, raising the possibility that DNA from the seat was transferred to them. It was also revealed that the two matches were stored in the same evidence bag, a practice a forensic expert told the court he had not come across before. Brian Shivers' DNA was also found on a mobile phone recovered from the car. However, in his judgement Mr Justice Deeney said the difficulty was that the DNA of at least three and possibly up to five individuals had been found on the phone. He added: "Matches and phones are in common use and the presence of DNA upon them was very different from its presence on guns or explosives." The judge said the prosecution had failed to eliminate other possibilities than the guilt of the accused, and that he was not satisfied beyond a reasonable doubt that Brian Shivers was guilty. Afterwards, Brian Shivers' solicitor said the police and public prosecution service have questions to answer about the decision to charge him. "The PPS it would now appear on an annual basis are responsible for exposing the public purse to millions of pounds in cases where there is no reasonable prospect of a conviction," Niall Murphy said. The scientific evidence in the first trial revealed that there was one contributor to the matches in question and the scientific evidence in the second revealed that there was more than one, so the fact that two scientists cannot even agree on what can only be described as a 50-50 question in circumstances where we are dealing with infinitesimal evidence is not safe and there needs to be a root and branch analysis of how that can occur. The solicitor also said Mr Shivers may now sue the PPS and the police for compensation. Another man, the prominent republican Colin Duffy, was also charged with the murders of the soldiers, but he was found not guilty in the original trial. Friday's verdict means no-one has been convicted of the killings.