An investigation is being launched into how authorities in Norfolk failed to stop a schizophrenic from killing his elderly parents - despite police being aware they had suffered violent abuse for more than two years.

An investigation is being launched into how authorities in Norfolk failed to stop a schizophrenic from killing his elderly parents - despite police being aware they had suffered violent abuse for more than two years.

A mental health charity said early intervention by the authorities could have prevented the brutal deaths last June of Arthur, 83, and Marguerite Dunkley, 80, at their home at Lyng, near Dereham.

Yesterday, a jury at Norwich Crown Court concluded that their schizophrenic son, Terrence Dunkley, 54, had stamped them to death before piling furniture on their bodies.

He was detained indefinitely at the Norvic Clinic in Norwich under the Mental Health Act.

Despite police being called to three violent attacks by Dunkley on his parents - the first in February, 2003 and which included punching his mother in the face and pushing her down the stairs - he had remained a free man, able to live in the community and to continue to see his parents unsupervised.

Mental health campaigners and MPs last night demanded answers as to how Norfolk social services, police adult protection teams and mental health officials remained unaware of the plight of the pensioners and of Dunkley's violent mental state.

But Norfolk police said it was Mrs Dunkley's insistence on protecting her son by refusing to press charges for the assaults - or even admit they happened - that had made it difficult for them or other agencies to act.

Dunkley was sectioned under the Mental Health Act after the February, 2003 attack and diagnosed with schizophrenia but was allowed to return to his home at Tottenhill, near King's Lynn.

Dr Hadrian Ball, of the Norfolk and Waveney Mental Health Partnership NHS Trust, said an internal investigation was under way, and he expected an independent inquiry to be launched by the East of England Strategic Health Authority.

Michael Howlett, director of the Zito Trust, which campaigns to improve mental health law, called for a full independent inquiry, saying the warning signs could not have been clearer.

“There is no justification for ignoring the seriousness of these acts of violence. We need to ensure that services intervene earlier,” he said.

“It just beggars belief that he should have been allowed to continue to have access to them unsupervised.”

Mr Howlett added: “They were completely defenceless - they must have been terrified. It is a very sad story.

“It looks as if this could have been prevented.

“There needs to be a full independent inquiry into what happened.”

A spokesman for the former West Norfolk Primary Care Trust, which was responsible for Dunkley's mental healthcare at the time, declined to answer questions about the matter.

Mid Norfolk MP Keith Simpson called for a government inquiry into the care provided for people with serious mental health problems. He said: “When you have a case like this it makes the public very worried indeed that people are being unnecessarily put at risk.”

A Norfolk police spokesman said no

charges were bought against Dunkley for the assaults because of his mother's denials, which had also meant that only the 2003 attack was referred to Norfolk social

services.

She said the police would undertake a routine review of its policy for dealing

with vulnerable adults in the light of the Dunkley case.

Lorna Payne, assistant director for community care with Norfolk County Council social services department, said her team had no idea of the sustained abuse that had been suffered by the Dunkleys.

She added: “Had they asked, or had a neighbour been concerned about their welfare in any way, the call would have been logged and appropriate action taken.”

Every year in the UK between 55 and 60 killings are committed by mental health patients, and 1,000 people who have been in contact with mental health services commit suicide.

Spurred on by reports into past tragedies, the government last month announced an amending mental health bill to improve patient supervision in the community. It is also reviewing how it assesses patient risk.

Because of Dunkley's illness, members of the jury in his case were told he was not fit to stand trial on two counts of murder and they only had to decide if he had committed

the act.

Speaking after the jury had delivered its verdict, the senior investigating police officer, Det Chief Insp Colin Pearce, said: “Norfolk Constabulary's major investigation team spent many months piecing together the evidence in this case, seeking expert medical opinion, using the latest forensic techniques and working closely with the Crown Prosecution Service to ensure that the offender was brought to justice.”

TERRENCE DUNKLEY

Terrence Dunkley was born on July 27, 1952 and looked set for a promising career in teaching. After college in London he studied for a teaching qualification at Keele, Staffordshire, before landing a job in Kingston teaching geography and sport.

With his career path set, he met and married a young Ukrainian, Ola Szuliga, a primary school teacher who was attracted to the “quiet, good-looking man”. But the couple struggled to support themselves financially and decided to move to Norfolk in the 1980s to be closer to his family.

They lived initially in a bungalow at Runcton Holme, near King's Lynn, but later sold the property and moved into a rented house in Green Lane, Tottenhill.

Dunkley struggled to find work, and it was during this time that his mental health started to deteriorate. Ola started noticing that her husband was suffering from “strange ideas”.

By 2000, and after violent outbursts from Dunkley, the relationship was in tatters and Ola left.

Neighbours said Dunkley became more isolated after the break-up. He stayed with his parents at Lyng for a few weeks, but their relationship was difficult and they suffered repeated attacks at his hands.

In the period leading up to June 12 he had a number of violent exchanges with his parents.

Mrs Dunkley confided in a friend that he had smashed up their furniture, which he had been storing for them.

She also said that, when she refused to let her son borrow her car, he smashed her head against a wall.

In early 2005, a neighbour, Georgina Clere, noticed Arthur Dunkley wearing a wound dressing on his head. Mrs Dunkley refused to press charges against her son and told her: “Terrence is my son, and you'll understand when you have a baby.”