Police believe a nurse and a first aider may have helped at the scene of a fatal car crash in Limavady at the weekend.
Ronald Moore, 22, from Bolea, died in the one-vehicle crash at Bishops Road on Saturday afternoon.
Three teenagers were also in the silver Vauxhall Insignia when the accident happened at around 3pm. They sustained minor injuries.
Police preparing a report for the coroner want to speak to a nurse and a first aider, who may have helped the victim but left shortly after the impact.
Witnesses are asked to contact police on 0845 600 8000 and ask for either the Collision Investigation Unit at Steeple Barracks, or police in Limavady.