Seven youths have been arrested after a 16-year-old boy was stabbed to death in west London.
Kodjo Yenga, of Portland Road in Notting Hill, was found with a stab wound on Wednesday evening. He died later in hospital.
Police arrested the boys after the stabbing which took place following a disturbance in Hammersmith Grove.
All seven, aged between 13 and 21 years old, are now being quizzed at separate west London police stations.
The Metropolitan Police said four of the youths were 13 years old, two were 15 and one was 21.
Police have urged anyone with information about the stabbing, which happened at about 1715 GMT, to contact them.
Det Ch Insp Tony Nash said: "We know there would have been a lot of people in the area at the time of the murder and I would urge anyone who saw what happened, or who has any other information about those responsible, to come forward to police."
Some flowers have been left outside the row of shops where the boy was stabbed.
One eyewitness, who did not wish to be named, said she had seen the teenager chased by a gang.
"I saw a fight at the top of the road. There were a big gang of guys chasing a guy with a dog, chucking sticks and shouting.
"I had to swerve my car because they were throwing things, and the police were there two minutes later," she said.
Another resident said she heard that the gang had been hitting the windows of a local convenience store before chasing the victim up the street.
The scene of the attack has been cordoned off.