Bedfordshire Police is appealing for witnesses following a fatal collision on the Bedfordshire/Hertfordshire border between Hexton and Pegsdon on Wednesday.
The incident occurred at around 1:15pm on the B655 Hitchin Road, involving a black Audi Quattro RS which was travelling east towards Hitchin, and a silver Kia Picanto, which was travelling west towards Hexton.
The driver of the Kia was taken to hospital with serious injuries, from which he later died.
Officers are keen to talk to the occupants of the Audi, who were not at the scene when they arrived. They are believed to be four men described as Asian and in their late teens or early 20s.
Insp Jamie Langwith from the Beds, Cambs and Herts road policing unit, said: “We are particularly keen to speak to the four occupants of the Audi, as well as anyone who was travelling along the Hitchin Road around the time of the collision and has a dash cam fitted to their vehicle.
“Someone may have captured footage of what happened prior to, or after, the collision and this would be extremely useful to our investigation.”
Anyone who witnessed the incident, or who has any information, is asked to contact police on 101 or use our online reporting tool.