A 21-year-old man has been stabbed to death on a high street in northwest London.
Police say a group of men arrived in two cars before blocking traffic to attack the victim in Harlesden at around 9pm last night.
After being stabbed, the victim ran into a bookmakers on the high street to get help.
Emergency services attended the scene and the man was taken to hospital, but he was pronounced dead just after 2.45am.
Seven men were arrested at the scene on suspicion of offences including possession of an offensive weapon and attempted murder.
A murder investigation has been opened and a post-mortem examination will be held in due course.
Detective Chief Inspector Glen Lloyd said: “I am appealing for anyone who witnessed this violent attack to come forward and contact the incident room.
“We know that the suspects blocked the road; this would have held up a number of vehicles including a Route 18 bus. Were you on this bus at 9pm?
“I would ask that anyone who filmed the assault on a mobile phone or who may have captured it on a dash cam to call us.
“It is important that we build up a picture of what happened on the High Street last night.”
Anyone with information can call police on 101 giving reference CAD 7897/23Apr, or, to remain anonymous, contact Crimestoppers on 0800 555 111 or online.