Police believe the driver of a car fleeing from police in Auckland overtook at least three vehicles before it crashed, seriously injuring the teenage occupants.
One of the four girls in the stolen vehicle has been interviewed and police hope to speak to another of the girls this week.
Two remain in hospital and are expected to have long-term stays due to the extent of their injuries.
Detective Sergeant James Robson believes at least three vehicles were overtaken between Ngapipi Rd and Nehu St, Orakei, just after the police pursuit started.
Another vehicle, a dark-coloured ute, was passed by police and the fleeing car just before the stolen vehicle hit a traffic island.
"From CCTV footage we've viewed it appears this vehicle was pulling over to let cars involved in the pursuit pass, so we'd like the occupants of this later vehicle, who are likely to be key witnesses, to contact Glen Innes CIB on (09) 524 1936.''