A witness has described seeing a neighbour "screaming erratically" while carrying out a frenzied attack on his mother in a park in Melbourne's north-west on Thursday afternoon.
Police swarmed John Coutts Reserve in Gladstone Park around 3:30pm after receiving multiple reports a man was "seriously assaulting an older female".
Officers shot the man dead within 30 seconds of arriving at the scene, after police said he refused to stop attacking the woman.
The dead man has been identified as Gabriel Messo, 31, and the critically injured woman was his mother Lilla Messo, 54.
The attack was witnessed by Mr Messo's neighbour, Sahan Panagoda, who was on a walk when he saw the incident unfold.
"I heard a car behind me at high speed, a marked cop car with its lights on … the passenger door was already open," he said.
The 26-year-old said he saw police run to a nearby field, where a man was sitting on the ground.
"His right hand was just going up and down. As the cops were approaching, he was just screaming erratically," Mr Panagoda said.
"Commands were being repeated to him, but I couldn't make out what they were saying."
Mr Panagoda saw Mr Messo fall to the ground after he was shot, but only realised later that the man was his neighbour.
"It was sad more than anything, but it was definitely a bit of a shock," he said.
Mr Panagoda's parents had recently rented a room to Mr Messo in the house next door, which was located opposite the reserve.
"We had no issues with him, he moved in to the house three weeks ago. He was a quiet guy, kept to himself," Mr Panagoda said.
"We didn't know much about him."
'Loving mother' frequently visited her son
Mr Panagoda said Mr Messo's mother was paying his rent and would visit three or four times a week to cook, clean and wash his clothes for him.
"She was a very sweet lady … she looked like a loving mother," Mr Panagoda said.
"They would always go on walks together in the park, so I guess it is surprising to realise that you're living next to someone who is capable of doing that to their own blood."
One of Mr Messo's housemates, Silvester, described Mr Messo as "always angry" and "not 100 per cent".
He said his mother was a regular visitor.
"His mother loved him. She was always coming here, bringing food and washing his clothes," Silvester said.
"I feel sorry for her, she's a very nice lady."
Silvester said he felt intimidated by Mr Messo's behaviour and would lock his door at night for protection.
"I was scared, I always locked my door because I don't trust him," he said.
"I know this guy is not right."
On Thursday night, Assistant Police Commissioner Luke Cornelius said Mr Messo was known to police but did not have a criminal record.
"We've had recent contact with him, but there was nothing in that recent contact with him that indicated to us that the events of today might have occurred," he said.
He described the incident as a "tragic event" and said based on what he had been told, the police officers had acted appropriately.
"They've been decisive, they've taken action and they have acted in a way to keep the community safe and stop what was a frenzied attack from continuing," he said.
The shooting is being investigated by the Homicide Squad and Professional Standards Command.
