A Sydney man has apologised for almost severing a baby's head after a judge found him not guilty of murdering her on the grounds of mental illness.
Days before the killing, Jayant Kumar Singh was released from a mental hospital after earlier telling staff of thoughts of wanting to strangle the baby.
He later told a psychiatrist people had conspired to place black magic spells on him involving "devilism".
After Justice Robert Shallcross Hulme delivered the not guilty verdict in the NSW Supreme Court on Tuesday, Singh said from the dock: "I am very sorry for what I have done."
The then 53-year-old had been babysitting the 10-month-old baby and her two siblings on December 22, 2006 at a house in Campsie, in Sydney's southwest.
"When the mother went to do the shopping, after a little while, I got a stick and hit the baby, then I used the knife and the chopper to cut the neck off," he told police.
The mother described Singh as being "very good with the kids" and said she had never seem him become angry or aggressive with any of them.
Justice Hulme said the post-mortem report revealed the baby had extensive fracturing to her skull, brain injury and her neck "had also been deeply severed with near decapitation".
Singh told police he had hit each of the two siblings once with a crutch after they started to cry and "tried to interrupt" him from attacking the baby.
"I hit them, they backed off," he said.
In the middle of 2006, Singh was admitted to hospital with blood sugar problems but some mental problems manifested themselves and he was transferred to Rozelle Mental Hospital.
The judge said he was released on December 12, when the mother said he was not the same person as before, always looking sleepy and not talkative.
But he still appeared attached to the children and never showed any signs of being angry or upset with them.
Referring to the Rozelle hospital notes, Justice Hulme said that on July 14 Singh described "guilty ruminations about strangling the baby" and on July 15 reported thoughts of killing the children.
After the death, one psychiatrist diagnosed Singh as suffering from major depression with melancholic and psychotic features.
He later said Singh suffered from "ongoing active symptoms of a significant psychotic disorder characterised by delusional beliefs of persecution".
The judge ordered that Singh be detained in a mental health facility until, and if, he is assessed as being no danger to the public.