A teenager was rushed to hospital on Sunday morning after being stabbed in the arm and back.
The 18-year-old victim was found suffering from the injuries at a house in Tonfield Road, Cheam, at around 8.30am but it is unknown whether he ws stabbed at the address or elsewhere.
An air ambulance landed in Gillian Park, just off Sutton Common Road, but the boy was transported to hospital by a ground ambulance.
Eyewitnesses said they heard the air ambulance circling above Cheam at about 9am.
Sutton police confirmed they are investigating an assault at an address in Tonfield Road on Sunday (Sept 12) when an-18-year-old man received injuries to his back and arm.
A spokesman for London Ambulance Service said: "We were called at 8.30am to reports of a stabbing. We treated a teenage boy who was taken by ambulance to a London hospital."
If you have any information that could help police with their enquiries please contact Det Con Brian Gillespie at Sutton CID on 020 8649 0747.
Alternatively, you can contact Crimestoppers anonymously on 0800 555 111.
Did you see or hear anything on Sunday morning? Call the news desk on 020 8330 9535.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here