A man accused of using an axe to kill a four-month-old baby in a pram claims he does not remember anything about the alleged attack, US police have said
Harold E Montague, 33, is also suspected of lashing out at the child's mother with the axe's blade during the rampage.
The woman has been left critically injured in the assault which happened in a street near the centre of Las Vegas.
Montague claims did not know her or the boy, according to officers.
The suspect is also accused of attacking his sister-in-law, a mentally disabled woman, more than 20 times with a point of the axe before bursting out of a house into the street.
Officers said she was stabbed repeatedly in the torso, stomach and legs. She is now in a stable condition at University Medical Centre in the city.
After Montague was interviewed by police, Lieutenant Lewis Roberts said: "We don't know what set him off.
"He claims he blacked out. He said he doesn't remember anything."
Neighbours saw the rampage and shouted at Montague to stop while they called the emergency services, Mr Roberts said.
Montague left the axe in the house before police arrived, and was involved in a scuffle with officers who tried to use a Taser gun to subdue and arrest him, said police spokesman Bill Cassell.
An officer suffered minor injuries that did not require medical treatment.
The baby boy was found dead in the street, near where his pram was discovered overturned.
His mother was taken to Sunrise Hospital and Medical Centre and has suffered what were described as disfiguring face and head injuries, said the Washington Post.
Mr Roberts also said Montague's wife was at work and two children were in the house during the attack.
Another child was at school. The youngsters were not hurt.
Montague is being held without bail on charges of murder, attempted murder and attempted murder of a police officer. He is set to appear in court next Tuesday