Detectives launched a murder hunt today after a teenager was stabbed to death in the street.
Passers-by dialled 999 after the 19-year-old was found collapsed in Stoke Newington, north London, last night.
Emergency services arrived at Yoakley Road shortly before 11pm and he was pronounced dead at the scene.
Scotland Yard said there were no reports of a disturbance and the circumstances of the stabbing are unclear.
A spokesman said investigators from the Homicide and Serious Crime Command will lead the inquiry.
The victim is the 12th teenager to be murdered in London this year and the ninth to be stabbed. There were 29 teenage killings in the capital last year.
The spokesman said that police know the man's identity and his next of kin have been informed.
The last teenager to be killed in London was Carl Beatson Asiedu, 19, who was stabbed to death in Kennington in August.
Senior officers have made huge strides tackling violence among young people since a slew of attacks last year.
Police figures show youth violence and murders have fallen considerably as the Met stepped up stop and search operations to trace those carrying knives.
Police said the teenager was stabbed after a row with two other men, who may have used a silver car.
Detective Chief Inspector John Macdonald, who us leading the inquiry, appealed for witnesses.
He said: "The victim was stabbed following an altercation with two male suspects. We also know that a silver vehicle left the scene shortly after the incident, travelling along Yoakley Road into Church Street.
"Were you in the area at the time? Did you see or hear anything suspicious? I urge anyone that has information that can assist this investigation to contact us.
"We retain an open mind regards motive at this very early stage."
A police spokesman said: "A post mortem examination is scheduled to take place today at Poplar Mortuary. An inquest will open and adjourn in due course."
He added that no-one has been arrested.
* Anyone with information is urged to contact the incident room at Barking on 020 8345 3985 or Crimestoppers on 0800 555 111.