The family of a Norfolk man decapitated by a friend suffering from paranoid schizophrenia have said they feel 'unbelievably let down' by the mental health service.

Sarah Rayner, the daughter of Graham Rayner, of Taverham, who was killed in May 2006, said the mistakes made by the former Norfolk and Waveney Mental Health Partnership NHS Trust were 'beyond belief'.

Ms Rayner, 38, was upset to read the report of an independent investigation into circumstances surrounding the death of her father, that stated it was 'predictable' that his killer, Garnet Hooper, might harm someone if he stopped taking his medication, which he had done a month before.

She was speaking yesterday in Norwich as the independent inquiry revealed that the death of her 64-year-old father at the hands of his friend Garnet Hooper may not have happened if a clinical team had taken different decisions and actions.

Dr Kiki O'Neill-Byrne, a member of the independent investigation team involved in producing the report, said: 'It was not just one missed opportunity, it was a whole series of things that led to a domino effect.'

The report concluded: 'It is the overall conclusion that the death of Mr Rayner on May 24, may not have occurred had the decisions and actions of the clinical team been different between May 5 and 24. However, preventability of his death is by no means certain.

'Absolute avoidability of this was dependent on him being treated in hospital either on a voluntary or a detained basis prior to this date.'

It also pointed to a number of 'lost opportunities' as the inquiry team gave seven recommendations for the Norfolk and Waveney Mental Health NHS Foundation Trust, which is now in charge of mental health services in the area.

This came after Hooper's brother told the independent team that he had concerns leading up to the tragedy, but did not feel that he had anyone to contact.

He said that if someone had made proactive contact with him, he would have shared his concerns.

Other mistakes included the decision to grant Hooper an absolute discharge from his detention under the Mental Health Act; a lack of an appropriate plan of action for his treatment; an absence of documented risk management and that the clinical team should not have allowed a reduction in Hooper's medication before he stopped taking it.

Sarah, who lives in north Norfolk, said: 'I am absolutely devastated by it. We feel unbelievably let down; it is beyond belief the mistakes that were made. Every time I read the report it makes me so angry. It is not something you can sit down and read in an evening; it is a catalogue of mistakes.'

Ms Rayner added that she was disappointed the report took so long to be produced and that lessons had to be learnt from the death of her father, a retired mechanic.

She said: 'In the final six weeks I can't believe nothing was done. It is a decision not to do anything.

'They could have phoned Garnet's brother and he would have said 'we are really worried about him', but nobody did anything.'

She added: 'It is just not good enough. I know they have made changes, but it is not good enough.'

Johanna Wells, 31, fianc�e of Mr Rayner's son, Adam, said: 'The report says clearly that it was preventable and predictable, so why was it not predicted and prevented?'

She added the amount of time waiting on the report has added to the enormous stress the family had suffered.

A statement she read on behalf of the family said: 'It is clear there were lost opportunities in the care of Garnet Hooper. We consider that the management of his care was the significant factor leading to the death of Graham.'

Dr O'Neill-Byrne said that there were a number of reasons for the delay in the report, including the need to go through more than 2,700 documents and more than 35 interviews. There was also a delay on the release of Hooper's notes.

Aidan Thomas, chief executive of the Trust, said: 'I fully accept today's report is critical of the care and treatment we delivered to our patient in 2006. However, the report also says 'it is not possible to do justice to the far-reaching changes made by our Trust since this happened'. 'We have already put every one of the report's recommendations into action.'

He said that the Trust worked with between 30,000-40,000 people in Norfolk and that a small minority had a risk that needed flagging on its new alert system.

Hooper had suffered from schizophrenia for 20 years and had been placed in a secure hospital in 1991 after stabbing his father.

In 1997, he was given an absolute discharge, although he was on regular medication. On April 24, 2006 it was established that he had stopped taking his medication – making it 'predictable' that he might harm someone again.

A month later he attacked his friend Mr Rayner with an axe and drove off with the headless body in his car. He was stopped by police on the A11 in Suffolk. Hooper was ordered to be detained indefinitely in a secure hospital after admitting manslaughter.