A mentally ill father believed he was compelled to kill his 12-year-old son to prevent Armageddon, a Sydney judge has found.
The then 30-year-old stabbed his son repeatedly before using the knife to seriously wound a neighbour and another man on October 9, 2010, at Liverpool in Sydney's southwest.
In the NSW Supreme Court on Friday, Justice Peter Johnson found the man - who cannot be named as it would identify his son - not guilty of murder by reason of mental illness.
He also was found not guilty of wounding the two men, aged 49 and 26, with intent to murder and to assaulting a police officer.
The judge was satisfied the man was suffering "an acute exacerbation of his chronic schizophrenic illness, and was hearing voices commanding him to act in the ways in which he did".
He also was satisfied the man did not know his actions were morally wrong.
The relationship between the boy's parents had ended, but the father sometimes stayed at the mother's home unit.
She was out when he repeatedly stabbed the boy before leaving the unit and stabbing a neighbour and a man visiting relatives in the block.
In his recorded police interview the next day, the man gave rambling answers, asserting "voices told me to sacrifice", if he did not "kill my own" then "Armageddon would occur" and "I am Armageddon ... I am a weapon ... of mass destruction".
With respect to the attack on the two men, he said: "If I didn't, I'd be used as Armageddon and the world would be blown up."
One psychiatrist said he had no doubt, from watching the interview, that "there was a very unwell man".
On occasions, the man asked about voices which he believed were real, asking police: "Did you hear that? They said I'm insane" and "Did you hear that? They said happy birthday".
The judge ordered the man to be detained as a forensic patient until, or if, he was deemed to not be a danger to the public or himself.
- AAP