Police have launched a critical incident investigation after a man killed himself on a Sydney street following a rampage which involved a carjacking and a bystander being stabbed.
The rampage started when officers attempted to stop a four-wheel drive not displaying number plates at Bass Hill before 3pm on Friday.
The 24-year-old driver rammed the police vehicle before dumping his 4WD at Chullora and stealing a small Woolworths truck which he drove to Rockdale, hitting a number of other cars on the way.
Detectives allege the man, who was known to police, then attempted to take another car and stabbed a bystander who tried to intervene.
The offender, who had a history of mental health issues, subsequently carjacked a taxi and drove north to Arncliffe where he was confronted by police outside St Francis Xavier's Catholic Primary School.
He then stabbed himself in the chest and died.
Acting Assistant Commissioner Mick Fitzgerald said the offender didn't have an extensive criminal history and wasn't trying to intentionally harm people.
The bystander who was attacked at Rockdale was in his early 20s and is in a stable condition at St George Hospital, authorities say.
One man told AAP his friend witnessed the attack.
He said the victim was stabbed in the stomach with a large kitchen knife after he ran out from a nearby gym to intervene.
The 24-year-old was heard arguing with others in Arabic, sources close to the investigation told AAP.
NSW Police said there was no indication the matter was terror-related and have launched an investigation which will be subject to an independent review.
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© AAP 2019