A man has admitted stabbing a cyclist to death in a south-west London park less than 24 hours after walking out of a psychiatric hospital.
John Barrett had a history of mental health problems and a violent past
John Barrett, 42, pleaded guilty at the Old Bailey to manslaughter on the grounds of diminished responsibility.
Barrett, from Putney, had spent 18 months in a secure unit after stabbing three people at an outpatients' clinic.
Former banker Denis Finnegan, 50, also from Putney, was stabbed to death in Richmond Park on 2 September last year.
Barrett, a paranoid schizophrenic, will be sentenced on 22 March.
The court was told Barrett had a history of mental health problems and was admitted to Springfield Hospital in Tooting, south-west London, as a voluntary patient.
Mr Finnegan was killed while cycling in Richmond Park
Doctors could not keep him at the hospital against his will although concerns about his condition had been so high that the Home Office had been about to order his recall.
Prosecutor Crispin Aylett said Barrett discharged himself and left the hospital "with what can only be described as terrible consequences".
Scotland Yard said Barrett first made for a DIY store where he bought a set of kitchen knives.
He then went to stay with a friend in Belsize Park, north London, promising to return the next morning, the court heard.
'Process of elimination'
But it was then that "the voices, he said, had returned - the voices, which in the past had said to kill himself, told him to kill someone else", Mr Aylett said.
Barrett took a taxi to Richmond Park and went on "what might be described as a lucid, but chilling process of elimination" as to who he would kill.
When Mr Finnegan cycled along a track he was attacked by Barrett who had armed himself with a knife, said Mr Aylett.
The court was told Barrett's case had prompted an inquiry by South West London and St George's Hospital Mental Health NHS Trust, which runs Springfield.
Trust chief executive Nigel Fisher said: "The trust very much regrets the events surrounding the death of Mr Finnegan.
"I am committed to ensuring that an in-depth analysis of the incident takes place to ensure we do all we can to prevent a tragedy of this sort happening in the future."
Mr Finnegan's brother John claimed a lack of money and a shortage of staff and beds had been to blame.
He said his brother would still be alive today if Barrett had been cared for properly.