Officers were called at 2.54am on Friday to reports that a man, aged 18, had been stabbed in an altercation at an address in Walshs Manor, Stantonbury, Milton Keynes.
The man was taken to Milton Keynes University Hospital, where sadly, he died of his injuries.
A second person, a 49-year-old man, was also stabbed in the incident, and has been taken to hospital with serious injuries, where he remains at this time in a stable condition.
The next of kin of the man who has died have been informed, and are being supported by specially trained officers, however, the victim has not yet been formally identified.
A 21-year-old man from Milton Keynes has been arrested on suspicion of murder and remains in police custody at this time.
Senior Investigating Officer Detective Chief Inspector Andy Howard of Thames Valley Police’s Major Crime Unit, said: “First and foremost, our thoughts are with the family of the man who has sadly died following this incident.
“Our officers were called to reports of an altercation at a property in Walshs Manor just before 3am, and upon arrival, found that an 18-year-old man had suffered life-threatening injuries as a result of the incident.
“Tragically, he has passed away, despite the best efforts of medical professionals at the scene and at Milton Keynes University Hospital.
“We have made an arrest, and I would like to re-assure the local community that although this will understandably cause significant concern, that this is not believed at this early stage of our investigation to be a random attack and that the victim and offender were known to one another.
“We have a scene-watch in place in Walshs Manor which is well-contained, and you will see an increased police presence in the area while our officers continue this investigation.
“This incident occurred inside a property, but I would appeal to anybody who was in the local area and believe that they saw or heard anything that could assist this investigation to please get in touch with police.
“You can do so by calling 101, quoting reference number 43210000167 or by making a report online here http://orlo.uk/7Y69C
“You can also call the independent charity Crimestoppers 100% anonymously on 0800 555 111, or if you see any of our officers in the vicinity, please don’t hesitate to speak with them.
“I would at this stage like to assure the public that we are conducting a thorough investigation, and have a suspect in custody, and we do not believe there to be any wider threat to the local community.”