A paranoid schizophrenic has admitted stabbing a hospitality worker to death in a row over throwing chips on a London bus.
Anthony Joseph admitted manslaughter on grounds of diminished responsibility after a murder trial jury was discharged for the second time.
Richard Whelan, 28, was stabbed seven times on a bus in July 2005.
Joseph, from north London, had been wrongly freed from prison even though an arrest warrant was outstanding.
He had been released after a sex allegation was dropped but should have been detained to face charges relating to a burglary offence.
The defence claimed the 23-year-old was suffering from the onset of paranoid schizophrenia when he carried out the attack on Mr Whelan, of Kentish Town, north London.
Following the verdict Mr Whelan's family said they were "very disappointed".
In a statement they said ""the defence of diminished responsibility in this case has been used as a defence for the un-defendable, with so much evidence showing that Anthony Joseph was an angry and vindictive man."
It added: "He has tried to excuse his actions that evening by claiming mental illness, however in our opinion he callously killed Richard for no reason at all."
Joseph had been released from prison earlier in the day despite an outstanding arrest warrant for him.
CCTV footage showed Mr Whelan struggling with Joseph shortly after he threw chips at Mr Whelan's girlfriend, Kerry Barker, 38, and another woman.
Miss Barker fought back tears as she told the court: "I turned round and they were fighting. The man was laughing as he was throwing chips.
Mr Whelan was stabbed to death on the top deck of the bus
"The man was basically on top of Richard," she said.
"Richard was trying to fight back and I remember trying to pull the man off Richard.
"I was ringing the bell. I was screaming 'Leave him alone'."
Victor Temple QC, prosecuting, said Joseph took out the knife and stabbed the unarmed Mr Whelan on a bus on the Holloway Road.
"The defendant had been drinking and taking drugs and needed little or no excuse to turn his pent-up anger against the innocent victim," he said.
Philip Katz QC, defending, said Joseph was suffering from the onset of schizophrenia at the time and should be cleared of murder on the grounds of diminished responsibility.
Joseph, of Islington, had been released from prison in Manchester only a few hours before the incident after a sex allegation against him was dropped.
But it appears he should have been detained because he was due to appear at another court for a burglary offence and there was an outstanding arrest warrant for him.
Although the bench warrant was on the national police computer, the prison was not told about it.
Joseph will be sentenced on 20 December at the Old Bailey.
Detective Chief Inspector John Macdonald said he was "disappointed" that Joseph was not convicted of murder.
"Our view all the time was that he was guilty of murder, he had the mental state to commit murder not manslaughter," he said.