Police can confirm that the 17-year-old boy found this morning with a stab wound in Thornhill, Southampton, has now died.
The 15-year-old boy arrested in connection with the incident has been re-arrested on suspicion of murder.
Detective Chief Inspector Liz Williams said: “We are still investigating how this young man has lost his life, and I would urge anyone who has any information – however insignificant they think it may be – to come forward and help us.
“We are conducting extra patrols in the Thornhill area; please either talk to our officers or call 101 quoting Operation Tint if you know anything that may help us. You can also call Crimestoppers anonymously on 0800 555 111.
“I understand that people in the community will be shocked and concerned by an incident like this, but I would ask people to please support our investigation and refrain from speculating on social media.”
Anyone with any information is asked to call us on 101 quoting Operation Tint or 44200022434.
Alternatively people can contact Crimestoppers on 0800 555 111, where information can be left anonymously.