Police have launched a murder investigation after a teenager was stabbed to death in south-east London. Officers were called to a street in Sydenham at 9.30pm on Friday but the 19-year-old man died at the scene. Officers from the Metropolitan police attempted first aid on the teenager and the London ambulance service also attended the incident at Miall Walk. The teenager’s family have been told but formal identification and a postmortem examination will take place in the coming days. DCI Chris Wood said the teenager’s mother visited the scene and officers have been supporting her and other relatives. He said: “Met officers have been working through the night to commence what will be a rigorous investigation into the death of this young man. Police cordons remain at the location as a painstaking forensic examination gets under way. “The victim’s mother has been to the scene and has met with officers. She and other family members will be provided with ongoing support, and my heart goes out to her as she faces up to the first day of the rest of her life without her son. “I can assure her, and indeed all Londoners, of my total commitment to finding the person or persons responsible for this murder and bringing them to justice. “The support of the local community, and of anyone who may know anything about this tragic incident, will also be crucial. If you have any information, please get in touch.” No arrests have yet been made.