Three teenagers from Luton have been arrested on suspicion of murder in connection with a stabbing on Hartsfield Road, on Thursday, March 22.
The Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit is investigating the death of 18-year-old Azaan Kaleem, who succumbed to his injuries on Saturday. His death is being treated as murder.
A 19-year-old man, an 18-year-old man and a 17-year old boy, were arrested yesterday (Sunday) and remain in custody.
A further man was arrested and released without charge.
Officers are appealing for anyone with information about the incident to get in touch.
In particular detectives would like to speak to the drivers of a dark coloured car, a small bright blue car, and a silver car, which were all seen driving along the road at the time of the incident.
Anyone with information is asked to contact police on 101 quoting Operation Bowen, or contact Crimestoppers, anonymously, on 0800 555111.