The death of a man decapitated by a mental health patient could have been stopped had there not been a catalogue of lost opportunities, an inquiry says.
Garnet Hooper, who had schizophrenia, attacked Graham Rayner, 64, of Taverham, Norfolk, with an axe on 24 May 2006.
The inquiry found Hooper had been without medication for a month.
As he had been violent before, "appropriate" action was needed when he stopped taking medication, it added.
Hooper, who was not named in the independent report, killed Mr Rayner then put his headless body in the boot of a car and drove off. The vehicle was later stopped by police on the A11 in Suffolk.
The then 53-year-old, of Attlebridge, later admitted manslaughter and was ordered to be detained indefinitely in a secure hospital under the Mental Health Act.
The report, published on Wednesday, says the team gave too much weight to Hooper's wishes and not enough to his past risk without medication.
It heard that 16 years before the killing, Hooper had attacked his father, who sustained near fatal injuries.
The report, commissioned by the East of England Strategic Health Authority, looked at his care by the former Norfolk Mental Health Trust - which has now become the Norfolk and Waveney Mental Health Partnership NHS Trust (NWH).
The report says had Hooper "not been allowed to extend the time gaps between his medication doses between January 2006 and 31 March 2006, and be without medication from 21 April through to 24 May this incident may not have occurred".
It says the mental health professionals failed to produce an "assertive plan of action" when it became aware that Hooper was not taking his medication in May 2006.
The report concludes: "The death of Mr Rayner on 24 May, may not have occurred had the decisions and actions of the clinical team been different between 5 and 24 May.
"However the preventability of death is by no means certain."
It called on the NWH to have a "robust system" to ensure the tracking of all patients who need after-care, such as continuing medication.
It said the trust must ensure that all medical staff know when patients may need to be assessed under the Mental Health Act, which can lead to compulsory detention.
Aidan Thomas, chief executive of NWH, said: "I welcome today's report. It quite rightly pinpoints weaknesses in care and risk assessment and management."
He said: "We have already acted on every single one of the report's recommendations, but we must continue to monitor this progress."