A 15-year-old boy has been arrested after a teenager was stabbed to death in a street attack.
The 18-year-old victim was found badly wounded in Neasden, north-west London, at 3.50pm on Friday.
He died at the scene in Tanfield Avenue from multiple stab wounds, Scotland Yard said.
The 15-year-old is being questioned by detectives on suspicion of murder.
A police spokesman said: "A crowd gathered around the victim soon after the attack and detectives are appealing for those who witnessed what happened or saw those involved leaving the scene after the attack to get in touch."
Police said a crime scene remains in place.