A 32-year-old woman was killed and two children injured when they were struck by a Jeep being followed by police.
The Jeep Cherokee was being followed by a police car
A police car was behind the Jeep Cherokee which was being driven in Sunderland on Thursday evening.
The police driver lost sight of the car but was directed by witnesses to St Luke's Road where a woman, her daughter and niece were lying in the street.
The Jeep was abandoned by the driver, who had disappeared and police said they were still trying to trace them.
It appeared the group was hit by the Jeep while they were still on the pavement.
All three were taken to Sunderland Royal Hospital where the woman was pronounced dead.
One of the children, an 11-year-old, suffered leg and arm fractures and a 10-year-old suffered fractures to both feet.
Both children are still being treated in hospital.
The incident has been referred to the Independent Police Complaints Commission (IPCC) because the Jeep was being followed by a patrol car before the collision.
Assistant Chief Constable Sue Sim said: "A full investigation is now under way into all the circumstances leading up to this crash and extensive inquiries are being carried out to trace the driver of the Jeep."