Police are being urged to do more to solve the rape and murder of Johnstone schoolgirl Pamela Hastie.

Defence lawyer Gordon Ritchie has slammed Police Scotland over the way it has handled the case.

Pamela, 16, was murdered in November 1981, with her body found dumped in Rannoch Woods, near her home.

Raymond Gilmour was caged for the killing in 1982 but always maintained his innocence, saying he had been forced to confess by police officers.

He was released on appeal in 2007 after it emerged he was a mentally vulnerable person who cracked under pressure from officers – leaving the murder unsolved.

Mr Ritchie worked on the appeal and was pivotal in ensure the miscarriage of justice was exposed.

And, speaking ahead of the Anatomy of an Investigation show which was broadcast at 1.30pm on BBC Radio Scotland today, he claimed police should have done more to bring Pamela’s killer to justice after his client was acquitted.

Mr Ritchie said: “It is regrettable that the police are not actively investigating this unsolved murder.

“To do so would require them to admit that their officers had abused their position and perjured themselves in the original trial – and I fear that this is a step too far for our force.

“It seems that the Hastie family may never know who murdered their daughter.”

Pamela was killed as she walked home through the woods on November 4, 1981.

Gilmour, who was a teenager at the time, was brought in for questioning after he admitted being in the woods the day before Pamela was killed – and exposing himself.

He was remanded in custody on a charge of indecent exposure and questioned about the murder.

His official statement taken by police that day states that, on the way back to his cell, he broke down, telling officers: “I can’t go on like this – I’ll have to talk.”

But Gilmour was released from custody after telling a detective superintendent the confession had been forced out of him.

Months passed with no new leads until Gilmour, on the way to court to face the indecent exposure charges, apparently confessed to police officers for the second time.

He was later found guilty at the High Court in Glasgow and sentenced to life in prison.

After this, he instructed Mr Ritchie and successfully appealed the conviction.

In 2007, three judges granted his appeal at the Court of Appeal in Edinburgh, declaring the original majority verdict unsafe after hearing “important and significant” evidence in the case.

At a 2006 court hearing, Professor Gisli Gudjonsson, an expert in interrogation and confessions, said Gilmour was emotionally disturbed at the time.

The professor in forensic psychology explained: “He was a vulnerable individual. If subjected to pressure he would not have coped well with that pressure.”

There was also fresh evidence regarding the significance of cuts found on Pamela’s fingers, no mention of which was made in the Crown pathologist’s report, which came from two other experts in forensic medicine.

One of the judges, Lord Gill, said he had noted discrepancies between Gilmour’s confession and the state of Pamela’s body.

It also emerged that, during the investigation into the murder, evidence was given to the police that could link notorious child killer Robert Black to the crime.

A van driver alleged that Black ran out of the woods and collided with his vehicle on the day that Pamela’s body was found.

Yesterday, a Police Scotland spokeswoman said: “The passage of time is no barrier to the investigation of unresolved murder cases and, in the view of Police Scotland, these cases are never closed.

“Homicide Governance and Review Department actively keeps all unsolved and unresolved homicides under review and meets regularly with the Crown Office and Procurator Fiscal Service in an attempt to review these cases and pursue resolution.

“Police Scotland, along with our partners in the Scottish Police Authority Forensic Services, continue to relentlessly pursue advances in technology and investigative approaches which help bring those responsible for serious and violent crimes to justice and provide answers for families of the victims of such crimes.

“Scientific and forensic developments, combined with information from the public and determined investigative work, can yield new opportunities in such cases.

“In addition, given the passage of time, personal circumstances and associations can change.”

Anyone who has new information about Pamela’s murder is asked to call the police on 101.