A paranoid schizophrenic, who admitted stabbing a mental health worker to death and threatened to kill the Queen, has been detained indefinitely.
Mental health worker Ashleigh Ewing was in her first full-time job
Ronald Dixon used four knives to kill Ashleigh Ewing, 22, who visited his house in Heaton, Newcastle, on behalf of charity Mental Health Matters.
The 35-year-old denied murder, but admitted manslaughter by reason of diminished responsibility.
Northumberland, Tyne and Wear NHS Trust will hold an inquiry into Dixon's care.
Miss Ewing, of Hebburn, South Tyneside, was found dead with 39 wounds in Dixon's kitchen on 22 May 2006.
Dixon, who believed he was Henry VIII's son, was also arrested last year outside Buckingham Palace for threatening to kill the Queen, Newcastle Crown Court heard.
Miss Ewing's parents, Jeff and Aileen, want to know why their daughter, who graduated in psychology the summer before her death, was sent to visit a dangerous client alone.
Miss Ewing was a support worker who helped clients with mental health problems to live in the community.
Dixon handed himself in to police after the attack
The court heard that Dixon used a number of knives during the attack because the blades kept snapping.
Paul Sloan QC, prosecuting, said: "He told police that his dad was Henry VIII.
"He admitted he wanted to kill the Queen. He referred to himself as King Ron."
Patrick Cosgrove QC, defending, said: "If responsible persons had taken other rational decisions at the crucial time, Miss Ewing would never have been put in the situation of grave risk and perhaps Mr Dixon would not have been at liberty to commit the crime."
He said Dixon had been refusing to take his anti-psychotic drugs, was drinking alcohol, and feeling stressed because of his debts.
A spokeswoman for Northumberland, Tyne and Wear NHS Trust said: "Since the incident we have carried out an internal review of our involvement in Ronald Dixon's care.
"We are satisfied that the individuals involved in his case acted professionally and provided appropriate support to him."
Police said Dixon had been receiving voluntary psychiatric treatment since being convicted of causing grievous bodily harm after attacking his parents with a hammer in 1994.
He received two years' probation for the offence and voluntarily attended Cherry Knowle Hospital in Sunderland for treatment.
Ronald Dixon had threatened to kill the Queen
After his arrest outside Buckingham Palace, he was sectioned then subsequently released into the community, where he was medically supervised by the Northumberland, Tyne and Wear NHS Trust.
Mental Health Matters managed the flat he lived in.
The mental health charity, Sane, criticised Dixon's treatment, saying a patient with a violent history should not have been allowed back into the community.
Chief executive, Marjorie Wallace, said: "It is incomprehensible that a seriously disturbed man with a history of violence and non-compliance with treatment should have been discharged from psychiatric care and allowed back into the community.
"It is also troubling that an inexperienced care worker should have been sent alone to Ronald Dixon's flat.
"There are 55 homicides and 1,300 suicides committed each year by people with a mental illness or disorder who have been in contact with mental health services during the previous year.
"This is another case which highlights how people can become lost in the 'black hole' between police, psychiatric and community services."