A JUDGE has postponed the sentencing of a man he described as a “bedroom Rambo” because he wants to understand how his mind works.

David Riding, 20, has been behind bars since being convicted of making a pipe bomb at the school where his father worked as caretaker.

He was due to be sentenced at Durham Crown Court, but Judge Christopher Prince said psychiatric and pre-sentence reports need to be more detailed.

A bomb disposal squad was called to Durham High School for Girls in November 2007 and police discovered a 13cm-long copper pipe bomb.

It had the word “killer” scratched on it and had been hidden in a locked safe under Riding’s bed.

The judge said the report should consider the significance of the discovery of two guns, live, blank-firing ammunition, three knives and a home-made knuckle duster.

Judge Prince said: “There is no mention of the other items recovered from the safe.

“I want the author to be fully aware of all of the items.

“I want to know what they make of the defendant.”

The court heard that Riding had shot a ball bearing gun at cans in woods with friends and used a knife to chop wood to start camp fires.

Judge Prince said the knuckle duster had been adapted with tape to protect anyone using it.

When he was convicted, the judge said he feared Riding might be capable of a “US-style high school massacre”.

He added: “I think that this is a cache of weapons.

“They themselves are not illegal, but if they demonstrate to me aspects of his personality that I find disturbing, then I will take them into account.

“There has to be for the judge as much information as possible.

“I think it is unrealistic to look at the pipe bomb and not the other items.”

Riding made the bomb from explosives from fireworks, which he dampened before use so he could safely handle the material, and waited months for it to dry.

Judge Prince said: “I reject that this is just idle curiosity. I want to know what is going on in his mind.

“I want a psychiatrist who has all the information.”

Sentencing was adjourned for three weeks for new reports to be prepared and will take place at Newcastle Crown Court on February 13.

An application for bail was refused and Riding was remanded into custody.