Three 14-year-old boys and a 15-year-old have been arrested on suspicion of murdering a man in his 60s.
Leicestershire Police said the victim was involved in an "incident" on Saturday, September 2 which was reported to the force on Tuesday, September 12.
He died in the early hours of Friday morning and a murder investigation was subsequently launched.
Police have not revealed the nature of the incident, but said the man was found injured on King Street, Leicester, at around 10pm on Saturday, September 2.
The arrested boys all remain in custody.
Detective Inspector Michelle Keen from East Midlands Special Operations Unit said: "We would urge anyone who may have been travelling in a vehicle or on foot around the time of the offence to come forward as you may be able to provide information which could assist our investigation."
Anyone with information is asked to call police on 101 or Crimestoppers anonymously on 0800 555111.