efe-epaSydney, Australia

A body found in a central Sydney residential building Tuesday is linked to an earlier stabbing attack that saw one woman injured and a man taken into custody, police said.

New South Wales Police said the body of a woman with knife wounds to her neck was found in the vicinity of where the suspect allegedly stabbed a 41-year-old woman in the back and attempted more attacks before bystanders managed to forcefully restrain him.

"At around 2 pm this afternoon we received multiple phone calls about a 21-year-old man from Maryong, in the vicinity of King Street, armed with a knife and wearing a balaclava," said NSW Police Force Commissioner Mick Fuller at a press conference.

"Over the next six minutes, I can only describe what would have been terrifying carnage in and around that area," he added.

Fuller said the 41-year-old injured victim appears to have been attacked at random. She was rushed to Sydney Hospital in an ambulance from the crime scene and was said to be in a stable condition.

Fuller said that in the 30 minutes that followed that stabbing, police found the body of an unidentified 21-year-old woman at a residential unit block near the area in Sydney's Central Business District and that all available information pointed toward the two crimes being linked.

"It is not currently classed as a terrorist incident," following an assessment by law enforcement and related federal agencies, Fuller said, though this would be re-assessed as the investigation progresses.

Police consider the suspect a "lone actor" with no confirmed links to terrorist organizations, the commissioner said, although a USB flash drive had been found on his person, which contained material suggesting "he had some ideologies in relation to terrorism."

When asked to elaborate, Fuller clarified that the flash drive appeared to contain information on other mass-casualty crimes committed in North America and New Zealand, a possible reference to white supremacist shootings such as the Mar. 15 attack against two mosques in Christchurch, New Zealand's third-largest city.

The alleged attacker was restrained by three civilians and several members of Fire and Rescue NSW who essentially placed him under citizen's arrest despite the large-bladed butcher's knife he was brandishing, Fuller said.

Several videos shared on Twitter by eyewitnesses showed the three men pinning the man down on the pavement using chairs and pressing a milk crate over his head until police arrived.

"The city tonight celebrates three brand new heroes," said NSW Police Minister David Elliott. "And I think it would only be appropriate for the commissioner and I to thank those three individual citizens who have acted well and truly beyond the call of any citizen in bringing this offender to bear.”

In one of the videos of the incident, the suspect can be seen jumping on a car while wielding the knife and repeatedly shouting “Shoot me in the (expletive) head!” followed by the slogan “Allahu akbar” (“God is greatest” in Arabic).

Police said the 21-year-old had a history of mental health issues and that they were looking into reports he had recently absconded from a mental facility.

Prime Minster Scott Morrison said on Twitter the attack was “deeply concerning.”

“The motivation for this attack has not yet been determined as Police are continuing with their enquiries… Our thoughts are with all those who have been impacted by this violent attack,” he said. EFE-EPA