The Police Ombudsman has been called in to investigate the circumstances surrounding the death of a teenager who was struck by a van in Co Antrim.
Shannon McQuillan, 19, was hit by the vehicle near Toomebridge at 3.40am on Saturday.
A 21-year-old man, who was also hit by the vehicle on the Moneynick Road, remained in a critical condition in hospital on Sunday.
A local councillor claimed that the teenager and the man were with a number of police officers shortly before the accident.
The PSNI said the incident was referred to the Police Ombudsman as is "normal established protocol".
A spokesman added: "Our thoughts at this time are with the McQuillan family and all of those affected by this tragic incident."
The PSNI said it would be inappropriate to comment further at this time.
Sinn Fein councillor Philip McGuigan said he was aware that a number of PSNI officers were with Ms McQuillan and the 21-year-old shortly before and a short distance from where the accident happened.
He added: "The family are determined that we get all the facts of what happened on the night and I fully support them in this endeavour."
Mr McGuigan said the additional information "has compounded an already grief-stricken family".