An adolescent has been captured on doubt of homicide after police were called to reports of an impact including three vehicles and a battle which occurred thereafter.
Officials found the person in question, in his 20s, with supposed cut injuries in Gammons Lane, Watford, just before 3am on Saturday.
He was taken to emergency clinic where he was articulated dead.
Police were likewise called to reports of another man who was found with a supposed cut injury to his arm in close-by St Georges Road.
The man was likewise taken to emergency clinic for treatment.
Police accept the two episodes are associated.
Watford Chief Inspector Matt Phillips stated: "I comprehend this dismal news will make alert the neighborhood network and I might want to console Watford occupants that we are working intimately with MP Richard Harrington and Watford Borough Council to help any individual who has been influenced by this horrible death toll."
Investigator Chief Inspector Justine Jenkins, from the Bedfordshire, Cambridgeshire, and Hertfordshire Major Crime Unit, said a 19-year-elderly person from Watford has been captured on doubt of homicide.
She included: "We are still in the all around beginning periods of our examination and broad enquiries are being completed to help set up the grouping of occasions.
"I would ask any observers or anybody with data to connect straight away.
"Specifically, I might want to get notification from any individual who accepts they may have dash cam film of any of the vehicles in Watford medium-term on Friday 30 August into early today."
The vehicles accepted to be associated with the crash are a dim Volkswagen Golf, a blue Vauxhall Corsa and a dark Vauxhall Astra, police said.