A wife watched on helplessly as her husband was allegedly beheaded by their son at their home in Sydney's west.
Toufic Zahab, 69, died after he was attacked with a brick and a knife inside the home on Stacey Street in Bankstown on Thursday morning.
Mr Zahab's son, Khoder Zahab, was arrested at the house just after 6am.
A relative at the scene said Mr Zahab's 42 year-old son Khoder, who lived in Villawood, had come over for dinner with his parents and had stayed the night.
Fairfax Media understands Khoder wasn't allowed to stay at his parents' home but had insisted he stay after dinner. His parents allowed him to out of generosity.
However, in the early hours of the morning, Khoder allegedly started attacking his mother and tried to push her down the stairs. One relative said the mother had possibly broken her hand.
When his father stepped in, Khoder allegedly attacked him with a brick and a knife.
"He come in and they eat dinner together and sleep inside and after that it happened," said a relative at the scene.
Mr Zahab, a retired carpenter, was described by the relative as a "very good but tough" man who had three sons and five daughters.
His grandson, Abdul, said: "Everyone's devastated and shocked."
"He was a wonderful man, a beautiful man, well known in the community.This is the most unexpected thing that could occur."
He said Khoder had a mental disorder that occasionally "triggered".
"Something must have set it off," he said.
Other relatives said he was a heavy drug user.
Mr Zahab's wife was taken from the scene in an ambulance and is providing a statement to police. Several other relatives including small children were at home at the time.
Detective Chief Inspector Glen Fitzgerald said the scene was so disturbing that police officers who attended had to be counselled.
He confirmed that Mr Zahab was founded decapitated.
Family members had scuffled with Khoder after the incident and detained him until police arrived.
"The scene is quite disturbing," Detective Chief Inspector Fitzgerald said. "It's been a difficult morning for both the family and police."
Police have set up a crime scene at the home, and homicide squad detectives have been called in to assist detectives from Bankstown Local Area Command.
The Transport Management Centre said all northbound lanes of Stacey Street were closed at the intersection of Macauley Avenue. One northbound lane was re-opened just after 8am.
- FFX Aus