A 17-year-old boy has been stabbed to death at a house party in West Yorkshire.
A large number of people inside were told to leave immediately.
Officers had been alerted by Yorkshire Ambulance Service who said a man from Leeds was suffering knife wounds.
He was rushed to hospital but was pronounced dead a short time later.
An eyewitness told Yorkshire Live: “I live opposite the house where the tragedy happened.
“They are new houses and have only been built a couple of months ago and this was the first party I think to be held there.
“The mood was fine, music was a bit loud but everyone was enjoying themselves. I thought no more of it and went to bed.
“It was only in the morning when I woke up that I saw all the police and the area cordoned off.
“Sadly the first party to be held there and it’s ended in tears.”
Detective Chief Inspector Alan Weekes said: “The loss of a young life in such sudden and violent circumstances is an absolute tragedy, and we are treating this incident very seriously and doing everything we can to identify those responsible.
“We are continuing to support this young man’s family at what is clearly an incredibly difficult time for them, and we are committed to getting them the answers they need as we progress our enquiries.”
West Yorkshire Police said: “Police have launched a murder investigation following the death of a 17-year-old boy in Leeds.
“At 2.48am this morning, police received reports of a disturbance at a house in Salisbury Grove, Armley, where a party involving a large number of people had been taking place.
‘A further call was received from the ambulance service who were responding to a male reported to have been stabbed at the address.
“Officers attended and dispersed people from the area around the address, and the victim, a 17-year-old boy from Leeds, was taken to hospital where he was pronounced dead a short time later.
“Detectives from West Yorkshire Police Homicide and Major Enquiry Team are treating his death as murder.
“A scene remains in place around the address in Salisbury Grove to undergo forensic examination and specialist searches.”
