Police were called at 1.48am today to reports that violent disorder involving a group of young men had flared near the Nuffield Hospital in York.
A few minutes later while officers were en route to the initial incident, a taxi driver called the emergency services to report that his silver Volvo S80 saloon car had been in a collision with a pedestrian nearby on Haxby Road.
The 21-year-old man died at the scene. His next of kin have been informed but he has not been named.
The stretch of road remains closed while police inquiries continue. Local diversions are in place.
Four local men, aged 22, 20, 18 and 18, have been arrested in connection with the violent disorder. Two women, aged 20 and 16, were also arrested on suspicion of assisting an offender.
The taxi driver, a 58-year-old man from York, is assisting police with inquiries in relation to the collision.
A 20-year-old man, who is believed to have been involved in the violent disorder incident, was taken to York District Hospital for treatment to a serious hand injury. He is assisting police with inquiries.
Det Insp Andrea Kell, of York CID, said: “This is clearly a very tragic incident and we are supporting the young man’s family while the police investigation continues.
“I urge anyone with information that could assist our enquiries to get in touch without delay.”
Officers are keen to trace a potential key witness who is believed to have witnessed the violent incident and collision after being dropped off by at taxi on Haxby Road at about 1.45am. It is understood that he had got a taxi fare to the location from Duncombe Place in York at about 1.30am.
The man spoke with an Irish accent and officers think he could have important information to assist the investigation.
Witnesses to the violent incident are urged to contact North Yorkshire Police on 101.
*Meanwhile in a separate incident West Yorkshire Police are appealing after a 38-year-old man was killed in an accident on Friday afternoon on Otley Road, Bingley, at 3.55pm.
He was in a Porsche Boxster that collided with a parked Mercedes Sprinter dropside lorry. Witnesses should call West Yorkshire Police on 101.