Police say they got a call just after midnight on Sunday about several youths being attacked by someone with a knife at a home in Clinton.
When officers arrived, they found three victims under the age of 18 injured. They were taken to hospital in Goderich, and one was airlifted to London where they remain. The injuries are all non-life threatening.
The suspect fled the scene before police got there but they did find the weapon they believe was used in the attack.
Police are asking anyone with any information, or anyone who was a witness to call police at 1-888-310-1122 or 519-482-1677.
