A man died after he was assaulted at a New Year's Eve party, police said.
Police and an ambulance were called to a house in Helmsley Close, Hockwell Ring, Luton, Bedfordshire just after 3am on Sunday.
The man, who has not yet been identified, suffered an assault and died a short time later of his injuries.
A spokeswoman for Bedfordshire Police said no further details about the nature of his injuries have yet been released.
Officers would like to speak to anyone who was at the party or who has any information about the incident.
The area is cordoned off and detectives from the Beds and Herts major crime unit, led by Detective Chief Inspector Melanie Burn, were called in to investigate.
Anyone with any information is asked to contact Bedfordshire Police on the non emergency number 101, or text information to 07786 200 011.
Alternatively contact independent charity Crimestoppers, anonymously, on 0800 555 111, or online at crimestoppers-uk.org.