Three people died and a fourth is seriously ill after their car crashed during a police pursuit early today, police said.
The two men and one woman were killed when their Vauxhall Vectra struck a garden wall in Oldham, Greater Manchester shortly after 3.30am.
A second woman in the car survived the crash and was taken to hospital where her condition is described as critical.
Greater Manchester Police said a police patrol earlier attempted to stop the car in Oldham town centre but the driver made off and the officer began a pursuit.
The crash happened shortly afterwards in Middleton Road, Chadderton.
A spokeswoman said: "GMP's Professional Standards Branch is aware and the matter has now been referred to the Independent Police Complaints Commission."
This morning the area around the crash site was sealed off by police. Forensic officers could be seen examining the overturned, burned out wreckage of the vehicle.
Paul Kelly, 40, a warehouse manager who lives about 100 yards from the scene, said he was woken up by a huge explosion at around 3.45am.
He said: "It was so loud I thought something had come into my house.
"I ran to the window and could see the car in flames.
"By the time I got out into the street the police were already here and they told me to go back inside.
"The ambulances arrived and then the fire brigade."
Mr Kelly had heard the vehicle arrived from the direction of Oldham, which, he said, meant it made a right turn into Middleton Road shortly before it collided with the wall.
He said: "There is a rise in the road as you make that right turn and it looks like the driver has lost control, hit the kerb a few times and spun round and overturned."