The Police Ombudsman's Office is appealing for information about an incident in Maghera, Co. Derry/Londonderry, during which a 21-year-old man fell from the back of a police van.
The man is in a critical condition in hospital after falling from the van at Church Road at around 1.20pm on Friday afternoon (January 27).
The incident has been referred by the PSNI to the Police Ombudsman's Office for independent investigation.
Police Ombudsman investigators have been at the scene and have photographed and mapped the route travelled by the van immediately prior to the incident.
A number of witnesses have already been identified, and investigators are currently conducting enquiries in the area in a bid to identify additional witnesses and CCTV footage.
The police van has also been seized and will undergo a detailed forensic examination this afternoon.
The Police Ombudsman's Office has appealed for anyone who saw what happened, or has any information about the incident, to contact them.
They are particularly keen to hear from anyone who saw the police van, a liveried Volkswagen Transporter, registration number GEZ 7867, as it drove along the Crew Road, Station Road and Church Road areas of the town at around 1.20pm on Friday.
Anyone with any information which may assist the Police Ombudsman investigation is asked to contact the Office's freephone information line, which is 0800 032 7880.