A teenager was found fatally stabbed in west London by police responding to reports of a fight in west London.
The boy, believed to be 17, was discovered with stab injuries outside a block of flats on Union Lane, Isleworth, at around 10.35pm on Friday.
Officers carried out first aid and paramedics were called to the scene, but the victim was pronounced dead a short time later.
Police tape sealed off part of the area on Saturday morning, with officers standing guard as shocked residents entered and left nearby flats.
Halima Abubaker, a 22-year-old hairdresser, said she saw two males "running for their lives" around the time of the incident.
She said: "I just heard loads of people, then there was seven police cars and two vans.
"I've lived here two years and nothing like this has happened. I feel really sick."
A restaurant owner, who has lived in one of the flats for seven years, said it was not something he expected to happen near his home.
The man, who did not wish to give him name, said: "It's a nice area ... We've never had a problem here before."
- Scotland Yard has launched a murder investigation and is asking anyone with information to contact officers on 101 or Crimestoppers anonymously on 0800 555111.