'Come eat my boyfriend' killer told doctors she want to commit mass murder

THE father of a man stabbed to death by his mentally ill girlfriend on Christmas Day says he feels let down by doctors who knew she was a danger to the community.

Tamie Melehan, 29, had been diagnosed with paranoid schizophrenia in 2002, hospitalised 20 times in seven years and had previously told doctors she wanted to commit mass murder.

She killed David Vaughan in the shower of her apartment on December 25, 2008.

Moments after slashing his throat, Melehan texted another boyfriend telling him she was going to eat the body because "I think he tastes good" and invited him over to join her.

In the NSW Supreme Court today, Justice Monika Schmidt said Melehan's plea of not guilty by reason of mental illness had been successfully made out and ordered that she be detained until the Mental Health Tribunal saw fit to release her.

But, speaking outside court, Mr Vaughan's father, Dr Alan Vaughan, said the family and the whole community had been left unprotected by the mental health system, which had not adequately supervised Melehan.

"According to the judgment there were warnings given about the defendant and about her danger to the community as far back as 2006 and she'd been in hospital for many years before that," Dr Vaughan said.

"Those warnings weren't acted on in a meaningful way.

"They still allowed her to be part of the community - sure treating her, but (she was) clearly not adequately supervised because it has resulted in my son's death.

"I would like to see that changed so that more appropriate care is taken of people who have severe mental illness."

David Vaughan's own experiences as a severe burns and car crash victim made him more empathetic to other people, both of his parents wrote in a letter to the judge.

But Dr Vaughan added he didn't think his son - who seemed pleased to have met someone - knew the extent of Melehan's problems.

"We think that he knew she had some problems but I don't think he knew the extent of the problems or the extent of the hospitalisation that she'd undergone," he said outside court.

Dr Vaughan said the family bore Melehan no ill will - they just hoped the mental health system would not let her down