Four people including police officer injured after car crash and alleged stabbings in Sydney’s south

Four people including a police officer have been injured after a driver involved in a Sydney car crash allegedly stabbed his passenger before lashing out at witnesses who tried to help.

Two vehicles collided at the intersection of the Princes Highway and Old Bush Road in Engadine before 9am on Sunday, New South Wales police said.

“Officers … arrived to find a man – who appeared to be suffering stab wounds – allegedly running from the crash scene. He was taken into custody with the deployment of a Taser,” a spokesperson said.

Supt Donald Faulds said witnesses reported his car had been driving erratically before colliding with the other vehicle.

Police alleged the 58-year-old male driver was attacking his passenger – a 48-year-old woman he was in a relationship with – with a box cutter while driving. The couple are from south-west Sydney.

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Investigators claimed the man suffered self-inflicted stab wounds to his neck. Faulds was unsure if that occurred before or after the crash.

After the collision, two witnesses approached the vehicle to check on the couple before attempting to help the woman. One of the bystanders, a man, was stabbed and later treated in hospital.

Police arrived on the scene after six minutes with an officer subsequently stabbed – suffering a serious laceration to his left wrist – when arresting the 58-year-old.

Six people in total were injured, including two people in the other vehicle and four people who received stab wounds.

The accused driver was in a serious but stable condition at Liverpool hospital. His female passenger was in a critical condition at St George hospital.

One bystander suffered abdominal injuries while the police officer received treatment for his wrist.

Faulds said the male driver was known to police but there had been no apprehended violence orders or domestic violence complaints regarding his current relationship.

The Cronulla Sharks chairman, Steve Mace, was driving his young son to football when they saw the crash.

Mace told News Corp Australia he ran to one of the cars to check if those inside were injured after he heard screams.

“I heard the guy screaming in the driver’s [seat] and then I heard his partner screaming even louder … I tried to open the [passenger] door and finally jammed it open,” he said.

“I saw him [allegedly] slashing her … I tried to drag her out of the car to stop the stabbing.”

Mace said he saw wounds to her neck, chest, stomach and legs.

He said he later attempted to protect the woman from the alleged attacker by putting her back into the car. Another onlooker who tried to help was stabbed, Mace claimed.

The Sharks chairman said the alleged attacker shouted: “We’re all dead anyway.” The driver was also allegedly angry the woman had “changed the radio station on him”.

A video captured by another passerby published by the ABC showed the alleged attacker running along the footpath and being chased by the police officer.

The NSW police minister, Yasmin Catley, said there was no ongoing risk to the community.

“That investigation is under way [and] I’ve been advised that the person of interest has been arrested,” she told reporters.

“There is no threat to the community. I want the community to know there is no threat whatsoever.”

The Princes Highway was closed in both directions and drivers were urged to avoid the area.