Why was thug freed one day before killing my son, asks mother

David Barker had broken off and dumped an electronic ankle tag imposed by a sheriff as an alternative to a custodial sentence and had then robbed a shop.

He was arrested and quizzed by the police, but was allowed to walk free because the police had no power to detain him for breaching his court tag. A day later Barker stabbed innocent teenager Robbie Thomson and dumped his body in a burn. He is due to be sentenced at the High Court in Edinburgh today.

Now Robbie's mother, Lorraine Scofield, is demanding justice secretary Kenny MacAskill explain why Barker was free to murder her son.

She said she wants to know how Mr MacAskill plans to close the legal loophole which let Barker out of custody to savagely murder the 17-year-old.

"I just want an answer. David Barker took his tag off two days before my son was murdered. During that two-day period he was arrested and let go again.

"Nothing is going to bring Robbie back. But if Barker had been kept in custody for taking off his tag, my son might still be here today.

"He had a tag on as an alternative to jail. Surely the minute he took that tag off he was committing a crime by breaching the order of the court?

"The police officers who investigated Robbie's death could not have been more helpful to me and my family and I want to thank them for that.

"However, I am considering making a formal complaint to the police just so there is an investigation into this and someone can give me an explanation.

"If Kenny MacAskill is planning to put more people on tags instead of jailing them, he should be made to explain why nothing happens when they break their tags."

It is understood Tayside Police were unable to hold Barker for breaching his tag because it was imposed as part of a sentence. As a result, tag operators Serco have to fill a report and send it back to the original sentencing court.

At Barker's murder trial, the jury was told he had fallen out with his girlfriend and left their home before ripping his tag off and dumping it. They also heard he robbed a shop and was arrested as the main suspect in the case - but was let go by police due to a lack of evidence against him.

By the time the police found more evidence linking him to the robbery, drug-fuelled Barker was already in the company of Robbie and just hours away from murdering him.

Officers from Tayside Police turned up at his home to try and re-arrest him two hours before Robbie was stabbed.

Ms Scofield, 41, said: "If something had been done before the 26 March this wouldn't have happened to my son.

"Something in the system is wrong, big time.He was arrested on (24 March] when he had already cut the tag off. It was a chance missed. That seems mad to me."

Barker was found guilty at the High Court in Dundee of murdering Robbie and dumping him in a burn in Coupar Angus on 26 March last year.