Detectives investigating the murder of 15-year-old Arsema Dawit are appealing for witnesses and information.
On arrival officers found a girl in a lift suffering from a number of stab wounds. She was pronounced dead at the scene. The victim has been named as Arsema Dawit.
A man believed to be in his 30s was arrested on one of the Golden Jubilee Bridges following the incident and remains in custody at a south London police station.
According to a Met spokesman it has been established that Arsema and the suspect knew each other but the exact nature of their relationship is unclear at this stage.
Police received an allegation of assault made by Arsema and her family in April this year, an investigation was set up and contact was made with the victim with a view to further progressing that investigation.
"At this stage I am trying to establish the true nature of the relationship between Arsema and the man in custody," says DCI Caroline Goode of the Homicide and Serious Crime Command.
"We are speaking to her family and friends to help build a picture of events leading up to the murder and to help piece together the relationship between them.
"I am also appealing to anyone who was in the area at the time of the murder and who may have seen or heard anything suspicious to come forward."
• Anyone with information is asked to call police in the strictest confidence on 020 8721 4868; alternatively to remain anonymous call Crimestoppers on 0800 555 111.