A man has admitted killing an elderly mobility scooter rider in a "motiveless" knife attack five days after being released from prison.
Lee Byer, 46, pleaded guilty to the manslaughter by diminished responsibility of Thomas O'Halloran, in Greenford, west London, in August 2022.
A group of children, one of whom called 999, tried to help the 87-year-old but he could not be saved.
A post-mortem examination found he was stabbed in the neck, chest and abdomen.
Police believe Mr O'Halloran, who had been playing his accordion near a supermarket, was attacked on 16 August as he passed Byer in an alleyway alongside the A40, out of sight of drivers.
Senior officers told the Old Bailey it was a "shocking act of unprovoked violence".
Byer, who has paranoid schizophrenia, was captured on CCTV running off and was arrested.
He had been caught on camera depositing a knife handle in a drain in Haymill Close on the way back to his mother's house. The blade was never found.
Grandfather Mr O'Halloran was originally from County Clare in western Ireland and had been well known in the local community.
He was said to have been a passionate musician and was described as "very popular" in Greenford, often busking for charity.
It can now be reported that Byer had 15 previous convictions for 30 offences dating back to when he was 14 and days earlier had been released from Wormwood Scrubs.
In 2011, he was convicted of robbery and was sentenced to 12 years in prison.
Byer also admitted having an offensive weapon on the day of Mr O'Halloran's killing.
Prosecutor Gareth Patterson KC accepted the pleas after mental health reports found Byer was psychotic, hearing voices, suffering from paranoid delusions and paranoid schizophrenia.
He said the defendant's mental state provided an explanation for what was a "motiveless attack".
Byer, of no fixed address, is currently being held at Broadmoor high security psychiatric hospital and is due to be sentenced on 10 May.
