A teenager is among two people arrested on suspicion of killing a 21-year-man in a road collision.
Police said a 17-year-old boy from Gloucester handed himself in earlier on Sunday and a 20-year-old man from Bristol was also arrested.
Officers were called shortly after 2am on Sunday to the A38 near Moreton Valence following reports of a collision involving a blue Mazda 6 which had been travelling north from Whitminster towards Gloucester.
An occupant of the vehicle, believed to be a 21-year-old man from Gloucester, died at the scene.
"Formal identification has not yet taken place but the man's next of kin has been informed," a force spokeswoman said.
"Officers are investigating as to whether a blue Audi A3 located nearby was involved in the incident.
"Police are appealing for anyone who has dashcam footage or who may have seen either vehicles prior to the incident to call police."