Jacky Amazing Feng allegedly killed his brother and parents in a drug-induced frenzy in their Sydney home and then returned to the “very grisly” crime scene an hour later after a surviving sibling called police. He is charged with three counts of murder and one count of attempted murder.

Emergency services were called to the Juliet Close home in Rosemeadow, near Campbelltown, just after 1.30am on Sunday by a man, aged 30, who had allegedly been assaulted by his brother.

Inside the home, police found their 65-year-old mother and 64-year-old father both badly injured.

Their mother was carried into the rear yard of the home but police and paramedics could not save her life.

Their father had suffered serious blunt force head injuries and was treated at the scene by ambulance officers. He was taken to Liverpool Hospital, where he later died.

Jacky Feng was charged with the murder of three members of his family in Rosemeadow.© Nine News

Police swept through the property and into a granny flat where they found the third brother, aged 25, dead inside.

The 32-year-old eldest brother, Jacky Feng, allegedly used a bladed and blunt weapon, potentially a hammer, to attack his family before fleeing the scene, early investigations suggest.

“It’s a very extensive crime scene. We haven’t recovered a weapon at the moment, but we are systematically working through the granny flat, and then we will go through the house,” Superintendent Grant Healey told reporters on Sunday.

“Police were confronted with a very bloody scene. Blunt force trauma is always horrendous for people to confront, and any edged weapon attack is horrendous to confront.

“So police and ambulance did a fantastic job in very trying circumstances.”

The silver sedan being towed as police watch on at the scene on Juliet Close.© Dean Sewell

At about 2.30am, Feng returned to the scene at Juliet Close in a silver vehicle.

Superintendent Healey said the family were not known to police.

“This is a very tragic incident that there was no way for us to predict this type of thing was going to occur,” he said.

Sources with knowledge of the unfolding investigation say it appears the alleged killer was affected by drugs.

Police at the house in Rosemeadow, where three people died in an attack on Sunday morning.© Dean Sewell

Healey said he could not confirm that yet. Police are working to piece together the missing hour.

“We’re trying to track his journey, so if anybody saw a silver sedan in the Rosemeadow area in that time of the morning, could they contact us, please,” Healey said.

Photographs from the scene showed a silver vehicle being towed away as forensic police entered the home and removed evidence in brown paper bags.

Police said they responded to reports of assault at the home.

A grey vehicle was taken from the scene in Rosemeadow on Sunday morning.© Dean Sewell

They found the bodies of a 65-year-old woman and a 25-year-old man, while two men – aged 64 and 30 – were found injured.

The older man was taken to Liverpool Hospital in a critical condition but later died. The younger man was treated at the same hospital and has since been released.

Feng was refused bail to appear before Campbelltown Local Court on Monday.

All five are members of the same family.

A report will be prepared for the coroner.