Jamal Coombes, who was 17, died in the early hours of Saturday.
Three other 15-year-olds have also been arrested on suspicion of murder.
Two have been released on bail, while one remains in custody.
Police were called at around 4.20am to reports of a stabbing on Glycena Road.
Officers attended with the London Ambulance Service and London’s Air Ambulance and found Jamal with serious injuries.
Despite the efforts of paramedics, he was pronounced dead at the scene.
Jamal’s family continue to be supported by specialist officers.
