Detectives are continuing to question four suspects as a schoolboy fights for his life in hospital after he was attacked in north London.
The victim, 15, who was stabbed in the chest, is in a critical condition in hospital.
Police and paramedics were scrambled to Southbury Road, near the entrance of Bush Hill park in Enfield at just before 9pm on Saturday,
Four people have been arrested and are in police custody where they continue to be questioned over the attack.
The boy's family are being supported by specialist officers.
Detective Sergeant Steve Ferguson, from the local policing team in Enfield, said: "A teenage boy has been left seriously injured and an investigation is under way to track down those responsible. Four people - two men and two male youths - have been arrested. They remain in police custody.
"Officers have recovered CCTV from nearby and a forensic examination has taken place. We would also ask that anyone who was in the area at the time of the incident, and saw or heard anything suspicious, to contact us immediately."
A police statement said: "We were called at 21:54hrs on Saturday, 20 January to reports of a stabbing in Southbury Road, near to the entrance of Bush Hill Park.
"Officers responded and provided first aid to a 15-year-old boy, who had been stabbed in the chest.
"He was taken to hospital where he remains in a life-threatening condition. His family have been informed."
Anyone with any information that could assist detectives is asked to call 101 quoting CAD 6623/20Jan. Information can also be shared online.
To remain anonymous contact Crimestoppers on 0800 555 111.
