A JUDGE has called on police to investigate a growing trend of younger people being involved in killings after he warned three defendants they faced life sentences for drunkenly beating a disabled man to death.

Judge John Milford's comments came as a 17-year-old youth, from Sunderland, who cannot be named for legal reasons, was yesterday convicted of the murder of Brent Martin following an 11 day trial at Newcastle Crown Court.

His co-defendants, William Hughes, 21, of Washington Road, Sunderland, and a 16 year-old youth, who also cannot be named, had already pleaded guilty to murder.

Mr Martin, 23, who had learning difficulties and had spent much of his life in psychiatric hospitals, was repeatedly punched, kicked, stamped on and headbutted by the three, who had bet each other £5 they could knock him out.

They chased their victim for a mile-and-a-half across two estates in Sunderland on August 23, last year, subjecting him to brutal assaults.

Mr Martin was left dying in a pool of blood next to a parked car in Baxter Road, Town End Farm.

The jury took four hours to convict the 17-year-old, who had pleaded not guilty, and who sat emotionless as the foreman returned the verdict.

Judge Milford warned the defendant and his two co-accused, who were not in court, that they faced a mandatory life sentence.

The judge said: "The only sentence I can pass is effectively a life sentence, but I must determine in due course the minimum term you will serve."

Toby Hedworth QC, prosecuting, told the court the three behaved like a pack of animals.

The 17-year-old told the court that he was not involved in the more serious injuries suffered by Mr Martin and had told the 16-year-old to stop when he saw things were out of hand.

The three will be sentenced at a date yet to be fixed.

Judge Milford revealed that he had requested statistics from the past decade of the number of killings involving another person in the Northumbria Police area.

On Monday 17-year-old Billy Dunwoodie, from Throckley, Newcastle, was detained indefinitely by a judge at Newcastle Crown Court after he stabbed to death 15-year-old friend Shane Jackson after the pair drank in the victim's bedroom.

Judge Milford said: "I am particularly interested in the growing trend where defendants are getting younger and younger.

"I have asked the police to give me statistics going back ten years for homicides within the Northumbria Police area."

Detective Superintendent Barbara Franklin, of Northumbria Police, who led the Brent Martin investigation, said: "We take note of the judge's comments and are fully aware of the concerns raised by this and other similar offences.

"We will provide a detailed response when the people convicted of this crime are sentenced."