A man was found stabbed to death in a block of flats in north west London on Tuesday morning.
The victim, in his 40s, was found by paramedics suffering from a stab injury in Mowbray Road, Kilburn at 10am.
An air ambulance was scrambled to the area but the man was pronounced dead at the scene.
Armed police swarmed the block of flats looking for the attacker.
There have been no arrests so far in the investigation.
A Met spokesman said: “Police were called by the London Ambulance Service to reports of a man stabbed at a residential address on Mowbray Road, NW6.
“Officers and London’s Air Ambulance attended. Despite their efforts, the man – who is believed to be aged in his mid-40s – was pronounced dead at the scene.
“His next of kin are yet to be informed.”
One local told The Standard: “There’s a whole team with surgical gloves, high vis jackets, big grey packs going up and down the stairs. I might be more cautious answering my door from now on.”
A London Ambulance Service spokeswoman added: “We were called at 9.48am this morning (20 December) to reports of a person seriously injured in Mowbray Road, Kilburn.
“We sent two ambulance crews, a paramedic in a fast response car, an advanced paramedic and an incident response officer to the scene. We also dispatched London’s Air Ambulance.
“Sadly, despite the best efforts of our crews, a man died at the scene.”
Anyone with information is asked to call police via 101 quoting reference CAD 1936/20Dec.