The victim has been named as Zaian Aimable-Lina who was from the local area.
Zaian was attacked in Ashburton Park on Thursday evening.
Officers who found him at around 7;30pm provided first aid but were unable to
save his life.
Yesterday a fifteen-year old youth was arrested on suspicion
of murder and taken to a South London police station.
He was later released on bail. Police have renewed their
appeal for witnesses.