A killer stabbed and battered his frail seven-stone victim to death in his own flat.

George Trainer knifed and beat frail David Graham after he complained about the killer damaging his phone.

Trainer then went on the run and left the 61 year-old for dead.

The next morning a friend of Mr Graham discovered him in his Glasgow flat, which he described as resembling a "war zone".

Mr Graham told police how he had been left "terrified" at the hands of Trainer. He recently suffered a heart attack and stroke and died in hospital after succumbing to his injuries.

A judge heard how Trainer was on licence at the time having been freed early from a jail term he got for serious assault. The 29-year-old was also under supervision in connection with another crime.

Trainer is now back behind bars after he pleaded guilty to a culpable homicide charge at the High Court in Glasgow. He was warned he faces a "significant" jail term when he is sentenced next month.

He is already serving more than eight years having been locked up for drug offences in April in Manchester. Mr Graham was attacked last July at his home in the city's Maryhill.

He had initially been enjoying "a great wee night" watching football on TV with some friends including Trainer's stepfather. Trainer himself then showed up but the victim wanted him out due to his "aggressive" behaviour.

The killer left but soon returned when Mr Graham was alone in his flat. Prosecutor Iain McSporran said that "for no reason" Trainer ripped a telephone from the wall.

As Mr Graham demanded to know why, Trainer grabbed his seven-stone victim and pushed him around.He went on to repeatedly knife, kick and punch his victim during a "sustained, prolonged assault".

Trainer fled the scene and it was the next morning when a friend discovered Mr Graham lying on the floor. He was described as "looking like a car crash victim" unable to talk and his head "all purple".

The court heard the flat looked like a "war zone" with blood everywhere and items smashed. A paramedic who arrived to treat the victim said he had "too many injuries to count". He also appeared to be suffering from hypothermia.

Mr Graham was taken to hospital and it was there he was later able to tell police: "I was terrified. I physically couldn't fight George off to defend myself as I'm only small."

He went on to suffer fatal pneumonia and died in mid-September, almost two months after the attack.

Mr McSporran said: "The violence inflicted upon him was not an immediate cause of that condition.

"Nonetheless, the totality of medical opinion is that the assault and subsequent hospitalisation was a material contributory factor in his death."

The court was told Trainer contacted his girlfriend after the attack claiming he was "going to get the jail" but said he could not remember what happened.

Police were unable to trace him and an appeal was launched with the public warned he "may pose a risk". Detectives later learned he had been held in Manchester in connection with drug offences before he was hauled back to Scotland.

The court heard Trainer was jailed for five and a half years in 2010 for assault before being released early from that sentence in 2013.

Trainer was also the subject on a community payback order at the time of the killing, which involved him being put under supervision.

He faced the charge of killing David having been brought from Strangeways prison in Manchester where he is serving eight and a half years.

Thomas Ross, defending, said Trainer could provide "no account" as to why he attacked the pensioner.

Mr Ross added: "Although he has no clear recollection, he was always willing to accept he was the person who assaulted Mr Graham." Sentencing was deferred until July 28 in Aberdeen.