Report clears forensic evidence in Kevin 'Gerbil' Carroll murder trial
Scotland's forensic science service has been cleared of any major failings over a prosecution relating to the murder of gangland figure Kevin "Gerbil" Carroll.
Judge Lord Brailsford criticised the quality of evidence after he acquitted Ross Monaghan of the fatal shooting in an Asda car park in Glasgow in 2010.
His comments resulted in a review of how the forensic service performed.
A watchdog has now ruled that forensic evidence at the 2012 trial was accurate and not subject to undue influence.
Mr Monaghan was cleared at the High Court in Glasgow after the forensic evidence against him was discredited.
A minute quantity of his DNA was found on the handle of one of the guns used to kill Mr Carroll.
This was discredited, however, when it also emerged that the DNA of a lab technician, who had never touched the gun, was also found in the sample analysed by forensic scientists, along with that of three unidentified men.
A single particle of firearms discharge residue was also found on a jacket seized during a raid of Mr Monaghan's Penilee home in July 2010.
That evidence was discredited when a firearms officer admitted that he and colleagues had been at a gun training exercise earlier, and were still wearing the same uniforms which would have been covered in discharge residue.
Lord Brailsford ruled that the particle was inadmissible as evidence because it was scientifically meaningless.
He said that it could easily have got on to Mr Monaghan's jacket through secondary transfer from the firearms officer's clothing.
Forensic expert Alison Colley, from the Scottish Police Service Authority (SPSA), told the hearing that a single particle was insufficient to draw any scientific conclusion from.
But she said she had been asked to form her conclusion using the particle at the request of a detective superintendent involved in the investigation.
The judge said he found her claim "disturbing".
Following the judge's comments, the SPSA, which was then responsible for forensic services now controlled by the Scottish Police Authority (SPA), asked the UK's Forensic Services Regulator (FSR) to review its handling of the case.
The results of the review, delayed until now due to legal proceedings, have concluded that the forensic science service acted properly.
Tom Nelson, Director of SPA Forensic Services, said: "I...was reassured that there was nothing improper in the liaison between our scientists and the police and that the evidence presented in this case was gathered as the result of an independent and objective assessment.
"I am encouraged that the investigation concludes that the evidence provided by Alison Marven and Laura Wilcock, the SPSA scientists in the Monaghan case, through the forensic report, precognitions and testimony, provided the prosecution, defence and the court with an accurate representation of the firearms evidence and its value."
Mr Nelson said the SPA had "accepted the minor recommendations made to improve our internal reporting procedures and the presentation of our court reports" and had "already implemented improvements in these areas".
In May last year, William Paterson was jailed for life after being convicted of murdering Mr Carroll.
He was told he must serve a minimum of 22 years in jail.