At about 10pm on Friday, August 25, a Subaru Impreza sedan left the road on The Grand Parade and crashed into a tree.
Two passengers, boys aged nine and 10, were taken to hospital, where they died.
A third passenger, a nine-year-old girl, was taken to hospital with minor injuries.
A 33-year-old man was taken to hospital under police guard.
He was charged over the crash and remains before the courts.
Police will allege the Impreza was involved in a street race with a silver Audi A4 before the crash.
Officers attended a home in Roselands at about 10.30am yesterday and seized an Audi A4 for forensic examination.
A 24-year-old man was arrested in Campsie yesterday afternoon.
He was charged with two counts of aggravated dangerous driving occasioning death, organising or promoting a race between vehicles, and two counts of failing to stop and render assistance after impact causing death.
He was refused bail and will appear in court today.
His licence was also suspended.
A 24-year-old woman, alleged to be a passenger in the Audi at the time of the crash, was arrested in Arncliffe at about 5pm yesterday.
She was charged with concealing a serious indictable offence.
She was bailed and will next appear in court on October 17.