THE father of a former detective wrongly accused of being at a crime scene has claimed the collapse of a murder trial shows lessons have not been learned since an investigation into his daughter's case, which centred on a fingerprint.

Iain McKie, whose daughter Shirley was exonerated by an inquiry, spoke out after Ross Monaghan was cleared on Friday of murdering gangland figure Kevin "Gerbil" Carroll when a judge ruled there was insufficient evidence to convict him.

The Home Office Forensic Science Regulator has agreed to investigate the circumstances surrounding the case after the court indicated that a forensic expert may have been placed under undue pressure to reach a conclusion on DNA evidence.

Now Mr McKie has voiced concerns about the close nature of the relationship between police and forensic services and warned of a continuing failure to ensure the independence of DNA investigations.

Mr McKie said: "One of the key messages in the inquiry report [into Shirley's case] was the closeness of police to the forensic experts. It's too close.

"This was identified by the judge in this trial and it was a crucial point in the McKie case. It's the same thing happening all over again."

The Carroll trial heard from forensic expert Alison Colley, of the Scottish Police Services Authority (SPSA), who said she was asked by a detective superintendent to form a conclusion using a single particle of gunpowder found on a jacket in Monaghan's wardrobe. The judge, Lord Brailsford, deemed it "of no evidential value" and described Ms Colley's evidence as "disturbing".

A small amount of DNA was also found on the grip of a pistol used to kill Carroll, which the court heard was a "perfect match" to Monaghan.

However, forensic experts were unable to say how it got there. Lord Brailsford said that a "more remote" transfer could not be excluded. The DNA of a lab technician – who had never touched the gun – was also found on the pistol.

Mr McKie said the case raised questions about changes implemented since the inquiry into his daughter's case, which cleared her of lying under oath in insisting the fingerprint found at the home of murder victim Marion Ross in 1997 was not hers.

She was later awarded £750,000 in an out-of-court settlement and has since received an apology from Strathclyde Police Chief Constable, Stephen House.

Mr McKie said one of the key messages of the 2007 McKie inquiry report conducted by Holyrood was that there was too close a relationship between the police and forensic experts.

He said: "Following my daughter's case and the massive inquiry, one would have hoped that things had changed, but in fact the SPSA is not following through with recommendations.

"We would hope that after what my daughter went through, this would have stopped, but it hasn't. The culture in the SPSA is poor.

"Until the SPSA get their act together, these mistakes will continue to happen and guilty people will go free and innocent people will be convicted for crimes they didn't commit."

After Monaghan's acquittal, the director of the SPSA's Forensic Services, Tom Nelson, said: "I take very seriously the suggestion that undue influence or pressure may have been placed on an individual member of forensics staff to reach a conclusion."

On the issue of a further inquiry, Mr McKie was sceptical. He asked: "How many do we need before they learn the lessons put in front of them?"

"They don't have proper scene-of-crime standards and when you don't have that you have contamination. They desperately need to sort this out.

"We've had recommendation after recommendation and they've never been put into practise and now we are faced with yet more forensic errors which put justice in jeopardy."