Toronto police say multiple shell casings and bullet holes were found in a car at the rear of a school parking lot in Scarborough on Wednesday afternoon.
Emergency crews were called to Cedarbrae Collegiate Institute near Markham Road and Lawrence Avenue East at 1:11 p.m. for reports of multiple gunshots heard.
The high school was on lockdown, however, it has since been lifted.
Police said they are looking for a man between 18 and 20 years old who stands between five feet 10 inches and six feet tall, has a slim build and is wearing a winter tuque and a red sweatshirt.
Officers are still on scene investigating.
The Toronto District School Board also put several elementary and junior high schools in the area in a hold-and-secure but that has since been lifted.