The brother of a man slain by a mental health patient says the insanity defence should carry a conviction.
Graeme Moyle says people like the man who killed his brother Colin should be accountable for their crimes.
Yesterday, Akshay Chand was found not guilty of killing teenager Christie Marceau, by reason of insanity.
Mr Moyle, who leads the Sensible Sentencing Trust's mental health group, says that ruling means he doesn't have a conviction.
"I would rather see it changed to a verdict of guilty but mentally ill, or guilty but insane, because currently there's no conviction attached to the result."
Mr Moyle says Chand can walk into a job once released, and if asked if he has any criminal conviction he can say with hand on heart he doesn't, even though he's killed somebody.
But the Crown Prosecutor in the Christie Marceau case says the ruling of insanity shouldn't be viewed lightly.
As a result, he will be detained as a special patient after killing the teenager on Auckland's North Shore in November last year.
Simon Moore QC says the detention is indefinite.
"It has no end, no specified end, and the only time it will ever have an end is when the Minister of Health is satisfied there's no risk to the public."
Dean of Canterbury University's law school, Dr Chris Gallavin says insanity is a valid defence to use, and an important one.
Dr Gallivan says if an offender doesn't know what they're doing, then they shouldn't be convicted.
He says it's important that criminal justice isn't used for serious medical issues.
A defence lawyer says Akshay Chand should have been receiving treatment and support for his mental illness when he was out on bail.
Marie Dyhrberg says a condition of Chand's bail was to attend the supervision and care facilities provided by mental health.
She says unfortunately that did not happen to the extent it should have.
"Unfortunately that did not really happen to the degree that should have been warranted and it may well be that had he had the supervision a lot earlier, once he was bailed, then the degree of his mental illness may well have been picked up before the tragedy occurred."
Photo: Christie Marceau (Supplied)