A KILLER known as the Black Dog Strangler has died in hospital after being found unresponsive in his prison cell, The Northern Echo can reveal.

Philip James Whiteman, 46, who sparked a nationwide hunt when he went on the run from a secure hospital last year, was being held at HMP Frankland in Durham. He was pronounced dead at the University Hospital of North Durham.

Whiteman, who was born Philip James Westwater, was on the loose in Newcastle for 12 hours in January 2013, before officers found him drinking in a gay bar.

The twice-married patient, who is from Newcastle, had been detained indefinitely under the Mental health Act after paralysing a man during a pub fight in 1989.

A year later Whiteman killed a fellow inmate at Liverpool's Ashworth Hospital with his dressing gown cord, convinced his victim had turned him into a black dog.

He admitted manslaughter on the grounds of diminished responsibility.

He fled St Nicholas Hospital, Newcastle, after asking to use the toilet during an escorted visit before disappearing.

Police and Crime Commissioner for Northumbria, Vera Baird, investigated his January 2 escape and said police were "lulled away from recognising Westwater's status as an escapee" as they often received reports of voluntary patients going missing.It took police three hours to upgrade Whiteman's status to "unlawfully at large" - but even then no risk assessment was done and no photograph released until about 10 hours after his disappearance.

Whiteman was re-captured less than two hours after a photo was finally released.

He married a nurse while he was a patient at high-security Rampton Hospital in 2008.

He and his bride, reported to be Claire Dudley, wed in a social club at the Nottinghamshire hospital.

A police spokesman said: “The death of a 46-year-old man has been reported to us by HMP Frankland.

“His death is not being treated as suspicious and the coroner is looking into it.”

A Prison Service spokesperson said: "HMP Frankland prisoner Philip James Whiteman was found unresponsive in his cell at 11.40am on Thursday November 13.

"Paramedics attended but he was later pronounced dead in hospital on Friday 7 December at 17.20.

"All deaths is prison are a tragedy and an investigation will be carried out by the Independent Prisons and Probation Ombudsman as happens in all such cases."

An inquest into his death has been opened and adjourned by County Durham coroner Andrew Tweddle in Crook.