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A mentally ill prisoner who strangled to death a pensioner who he thought looked like SANTA has been jailed for life.
David Gomersall, 25, grabbed former peacekeeper John Coxall, 80, in a headlock before choking him with bed linen on December 3.
Coxall had been serving 30 weeks for breaching a restraining order and was watching snooker when he was attacked at HMP Nottingham.
A court heard the pensioner tried to shout "help me, help me" as he was brutally throttled in his cell before being discovered by prison guards.
Gomersall was found guilty of murder and sentenced to life in prison, of which he must serve a minimum of 13 years, at Nottingham Crown Court yesterday.
The court heard he had spent time at Arnold Lodge, a medium secure psychiatric hospital in Leicester, before he was moved back to the prison.
Gomersall had been due to see a mental health nurse on the day of the killing but failed to attend.
Now relatives of Mr Coxall, who had served as a United Kingdom peacekeeper abroad, have demanded an inquiry into the brutal murder.
His brother-in-law Peter Joliffe, said in a statement that Mr Coxall, of Long Eaton, Nottingham, had served his country and worked hard all his life and was regarded as being "reliable, dedicated and conscientious".
One relative from London, who asked not to be named, said: "I'm absolutely outraged how he died.
"I think it's an absolute disgrace that this was allowed to happen and there should be a separate inquiry by the Ministry of Justice."
Sentencing, Mr Justice Holroyde said the pensioner must have died in "great pain and very great terror".
He added: "Mr Coxall served his country as a peacekeeper in a foreign land.
"He lived a hard-working life in the postal service and rendered public service for many years.
"It was a wretched end to such a life."
In a transcript of his police interview played to the jury he said to officers "the voices" told him to do it.
He later told detectives: "How can you kill Santa, man."
Gomersall, who was serving three years for threatening to kill someone, said: "I grabbed him in a headlock.
"I had a piece of bed sheet wrapped around my hand.
"I kind of choked him with the bedding sheet thing. He looked like Santa.
"How can you kill Santa, man?"
He said he thought he heard voices telling him to kill when he attacked Coxall, who was in jail for breaching a restraining order over an ongoing neighbour dispute.
Jurors heard a prison officer found Coxall dead on the floor of his cell after Gomersall confessed: "Gov, I'm hearing voices and l've killed the man in 215. I'm serious, Gov."
Gomersall told Detective Constable Emma Braybrook, from Nottinghamshire Police, during interview: "The voices kept telling me to kill him."
Prosecutor Shaun Smith QC said: "Even though family did not see him regularly, they had contact with him and, of course, they are shocked about hearing how he died, because they expected a phone call to say he died because he was an old person.
"They were very shocked indeed."
After the verdict, Detective Inspector Justine Dakin, of Nottinghamshire Police, said: "With Gomersall's history of offending and mental illness, including an apparent interest in elderly men, John Coxall's age and his vulnerability made him the ideal target for Gomersall, who appears to have been determined to kill someone on that day.
"John, or 'Jack' as he was known to his family, was an old and frail man. I would like to pay tribute to his family, who recall an intelligent and deeply religious man.
"This has been a huge shock for them and has had a significant emotional impact. They were unaware Jack was in prison until news of his death was broken to them.
"In addition to the work of detectives working on the case, I would like to thank the staff of HMP Nottingham for the work they did to preserve vital evidence before the police arrived at the prison, which has helped to secure the conviction of a very dangerous individual."