Police Ombudsman investigators have appealed for anyone who saw the car which crashed near Castledawson last week killing its two occupants to contact them.
Two men died when the white Honda Civic crashed near Castledawson on Thursday night.
Its understood the car, which may have been stolen in Letterkenny, had been followed at one stage by police as it travelled along the Glenshane Pass.
Police Ombudsman investigators today revisited the route taken by the car from a point on the Glenshane Pass near the Ponderosa Restaurant on its route towards Dungiven, through the Castledawson Roundabout and onto the A6 towards Belfast
The car then hit three vehicles, before rolling down a bank, killing its two occupants.
Some of those in the other vehicles were seriously injured and remain in hospital.
Police Ombudsman investigators have spoken to witnesses who saw the vehicle prior to, at the time of and following the crash.
They are particularly keen to talk to anyone who saw the car between 9.15pm and 9.35pm along the route.
What might have been particularly significant about the car is that it may have been travelling without number plates.
We would also be keen to talk to anyone who saw it on its route from Letterkenny, including anyone who may have seen it stopping at any occasion.
Anyone who may have information has been asked to contact the Police Ombudsman's Office. Telephone: 028 90 828653 or 028 90 828685.