A young man was murdered in a “senseless” attack when a large house party in north-east London spiralled out of control, police said.
Officers were called to a flat in Stamford Hill, Hackney, at 12.50am on Saturday following reports of a fight.
A 20-year-old man and a 17-year-old were found with stab injuries and rushed to hospital, but the older of the two was pronounced dead at 4.30am.
The teenager is expected to survive, while another man, aged 24, was also taken to hospital with a non-life-threatening head injury.
No arrests have been made and detectives have appealed for anyone with information to come forward.
Detective Chief Inspector Andrew Packer said: "Another family has been left devastated by the senseless loss of a young life to knife crime, and we're doing all we can to bring those responsible to justice.
"What we know so far is that all three of these victims appear to have been attending a large house party at the address on Wilderton Road.
"I want to hear from anyone who was at that party, even if they didn't witness the assaults they may have some information that could help us piece together the course of events that led to this tragedy.
"We will continue to work tirelessly on this case, but as ever we need witnesses to come forward and tell us what they know."
Anyone with information that may assist the investigation is urged to call the incident room on 0208 345 3865 quoting CAD 297sep22.
To remain anonymous contact Crimestoppers on 0800 555 111 or via the https://crimestoppers-uk.org/ website.