NHS failings allowed Timothy Crook to batter his parents to death and Michael Harris to fatally stab friend, inquiries conclude

A raft of failings by mental health teams and managers contributed to three shocking killings in the same town in the space of four months, investigators have concluded.

Timothy Crook battered his elderly parents, Bob and Elsie, to death with a hammer at their bungalow in Swindon in 2007, before hiding their bodies in a garden.

Just weeks before, Michael Harris fatally stabbed his friend Carl James, 21, in front of his young family at his home in the Wiltshire town.

Two independent investigations into the three killings concluded that they could have been prevented.

In the case of Crook, it was concluded that policy and procedure were "systematically ignored". The report revealed how Crook's sister, Janice Lawrence, repeatedly sought help because she was so worried about her brother but was not heard.

The report on Harris ruled that an "accumulation of poor practice, failures in systems" and a lack of "managerial direction and control" were "causal factors" in James' death.

Crook was diagnosed in 2002 while living in Lincoln as having a delusional disorder but discharged himself from hospital. No care plan was put in place and, though he was considered a risk by police, he was able to slip through the safety net of care, according to the report.

Crook moved to Swindon to live with his father and mother, 83 and 76. His sister tried to get treatment for him but her concerns about her brother's behaviour were not taken seriously.

In July 2007 Crook, 44, attacked and killed his parents. He was sentenced to an indefinite period of detention at a high security hospital.

The report on his case says Crook had "a well-documented risk profile developed by Lincolnshire police service". But "this risk profile was minimised by both Lincoln and Swindon mental health services".

It continues: "The deterioration of [Crook's] mental health was almost certainly preventable had it been managed in a professional and robust manner."

The report concludes: "Both the Avon and Wiltshire Mental Health Partnership NHS Trust and the Lincolnshire Partnership NHS Foundation Trust failed to deliver the required standard of care and treatment to Mr Crook.

"This is particularly so in relation to the Avon and Wiltshire Trust whose failure to respond to information received fell far short of any acceptable standard."

Harris, who was 20 at the time of the killing in March 2007, was made the subject of an indefinite hospital order after pleading guilty to manslaughter on the grounds of diminished responsibility.

He had first been referred to mental health services in 2004. Harris was a heavy user of cannabis and was expressing "suicidal and homicidal ideas".

He spoke of a desire to kill both his friend, Carl James, and a fictional character from a television series. He remained under the care of mental health services until he carried out his threat and killed James.

The report on Harris concludes his treatment was "fragmented" and there was a "range of missed opportunities" and "failures by individuals and in systems."

If "readily available information" had been shared those involved in his treatment they would have realised that Harris's mental health was deteriorating to such an extent that he would probably have been admitted to hospital ? and so would not have been free to kill.

Eighty service improvement recommendations are made to Avon and Wiltshire in the two reports, which were commissioned by the South West Strategic Health Authority and published on Tuesday. It said that 70 had been implemented and they were working on the 10 remaining.

Hazel Watson, director of nursing at Avon and Wiltshire, apologised to the victims' families. She accepted that the concerns expressed by Crook's sister were not listened to. "She asked for help and we didn't hear her,"she said.

Among the improvements she said had been made were the way the concerns of people such as Ms Lawrence were dealt with and how records were kept.

Lincolnshire Partnership NHS Foundation Trust also apologised for its failings and said the 12 recommendations that had been made to it had been implemented.