A 17-year-old boy has died after being stabbed in east London.
The teenager was found in Longshaw Road, Chingford, at around 9.20pm on Easter Monday, the Metropolitan Police said.
Teams from both the land and air ambulance services as well as members of the public tried to save him but he died at the scene. His family has been told.
A friend told news website MyLondon that a man had jumped out of a car and chased the victim before stabbing him.
He said: “I was with him yesterday and it happened three hours later after I left. We were just chilling minding our own business.
“I went out with my dad and got home, then got a call saying your friend had got stabbed at the bottom of your road. I could not get past the tape.
“He was with his friend, they were walking this way and a guy jumped out a car and appeared out of the dark, pulled a knife out and started running after them.
“One ran that way and my friend ran that way and the guy targeted him for some reason.”
Detectives are viewing CCTV and carrying out door to door inquiries, and have already spoken to some witnesses, although they are keen to hear from anyone else who has information about what happened.
Chief Superintendent Simon Crick, local policing commander for north-east London, said: “This is a tragic incident and I am devastated that a young life has been lost as a result of knife crime.
“My thoughts are with the victim’s family at this incredibly difficult time. Incidents such as this have a devastating impact on families, friends and our local communities.
“We have a dedicated team of detectives working on the investigation. They have been at the scene overnight and will remain there today as they carry out further enquiries.
“This work is being supported by additional local patrols who are there to respond to any concerns within the community.”
He said: “I join the community in expressing deep sadness following an incident yesterday in which a 17-year-old male tragically lost his life.
“I urge anyone who knows anything about this shocking crime to contact the police.
“The council is working closely with local police colleagues to reassure the community, and we will provide extra presence in the area over the next few days.
“Please speak to our neighbourhood officers about any concerns you have when you see them. They will listen and take forward these concerns as we work to make the area safer.
“Too many of our young people are afraid of violence in Waltham Forest when they should instead feel secure.
“We and our partners are using all the powers and tools available to us to make our community a safer place where young people and their families can enjoy their lives.”
Witnesses can contact police in the incident room on 020 8345 3985 or by calling 101 or on Twitter at @MetCC quoting the reference CAD 6358/10Apr. To remain anonymous contact Crimestoppers on 0800 555 111 or online.