Detectives have launched a murder inquiry after a boy believed to be 16 was stabbed to death.
The teenager, who has not been named, was killed in south east London in the early hours of Wednesday.
Emergency crews were called to Launcelot Road, Lewisham, at 4am but the victim was pronounced dead shortly after 5.10am. His next of kin have been informed.
Three teenage boys aged between 16 and 18 remain in custody after being arrested by the Metropolitan Police.
The stabbing happened inside a house in the tree-lined residential area close to two schools.
As forensic examinations were carried out, the boy's body remained at the scene. Officers were on duty at a cordon as searches continued to take place around the property.
Jordan Hughes said the neighbourhood had experiences with violent crime before: "There's always been trouble in this area, a kid got stabbed in the neck around here a couple of months ago. It's not a nice thing to happen. Everyone is a bit shocked by it."
A force spokesman said: "We retain an open mind as to the motive at this early stage and are actively seeking any information, which can be provided in confidence."
Distraught relatives of the teenager attended the scene but were too upset to talk publicly about what had happened. It is understood the stabbing took place during a house party.
One neighbour was woken by screams in the middle of the night. "It was around 2.30am and I heard these shouts and screams," said the woman, who did not want to be named. "It started to get louder and louder and when I got up to look out about 3.15am I saw all these people running away from the house. I went into a bit of shock then about what happened. I have been up since and haven't slept. It's just awful what's happened."