A 41-year-old man has died while in police custody in Sydney's south-west overnight.
Police were called to the M5 motorway at Moorebank about 3.35am after reports a man was running in and out of traffic on the eastbound lane.
Upon arrival, police attempted to arrest the man before having to deploy pepper spray.
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A short time later, the man lost consciousness.
He was taken to Liverpool Hospital by paramedics but was unable to be revived.
Assistant Commissioner Stuart Smith, Commander of the South West Metropolitan Region, said the scene was "quite confronting" for officers.
A critical incident team from the State Crime Command's Homicide Squad will investigate the circumstances surrounding the man's death.
The investigation will also be subject to independent review.
Police are appealing for anyone who was on the M5 about the time of the incident and has relevant dashcam vision to contact Liverpool Police.
