A girl aged 16 has been re-arrested on suspicion of murder following the death of an 18-year-old man who was stabbed in the street.
Scotland Yard said officers were called by London Ambulance Service to an incident in the high street in Sydenham, south east London.
The wounded man was taken to a south London hospital, where he died of his injuries early today.
A Yard spokesman said that although the victim has not been formally identified, he could be named as Nathan Murray, of Sydenham. A post-mortem examination will be held in due course.
The 16-year-old girl from Lewisham, who was arrested yesterday for grievous bodily harm with intent, was re-arrested today on suspicion of murder. She remains in custody in a south London police station.
Detectives from the homicide and major crime command are investigating.
Anyone with information is asked to contact the incident room on 020 8721 4961 or, if wishing to remain anonymous, Crimestoppers on 0800 555 111.