The man who killed Auckland teenager Christie Marceau while he was on bail masked the severity of his illness from doctors, with his schizophrenia diagnosed only after he stabbed her to death.
Akshay Chand, 19, was found not guilty by reason of insanity, after stabbing Ms Marceau to death in November last year.
Chand was on bail facing charges of kidnapping and threatening to rape Ms Marceau when he killed her.
The police opposed bail, fearing Chand might reoffend.
Court documents show a psychiatric report provided to the judge before he was released described him as suffering depression, but deemed him fit to stand trial.
A series of psychiatrists saw Chand following the kidnapping, but in each case he was diagnosed with depression.
It was only after Ms Marceau's death that Chand disclosed he had voices in his head.
Prison guards ask for more training
The union for prison guards says the killing of Christie Marceau by Chand shows guards need more training to spot signs of mental illness.
Psychiatrists say he was having a schizophrenic episode, which started when he was in custody two months earlier on charges of threatening Ms Marceau.
A psychiatric report at the time said Chand was suicidal, not homicidal, but also said he acted strangely.
The Corrections Association says guards did not know Chand was considered an at-risk prisoner, and says they also need more in-depth training in recognising signs of mental illness.
The High Court in Auckland has ordered Chand detained indefinitely in a mental health unit.
Bail laws being considered
MPs are making no promises the case will have a direct impact on the new bail laws making their way through Parliament.
The law and order select committee is considering a bill to make it harder for those accused of serious offences to get bail.
It is also looking at the 58,000-signature 'Christie's Law' petition which calls for a tightening of the bail laws.
Labour MP Phil Goff, who is on the committee, says the petition is only marginally feeding into the bill but will be considered in its own right at a later date.
Associate Justice Minister Chester Borrows says it is up to the committee to decide whether it incorporates elements of submissions by the promoters of Christie's Law into its recommendations.