The stabbing occurred inside a combination Tim Hortons/Wendy's restaurant located at Britannia Road and Terry Fox Way.
Peel Regional Police say that a man was sitting at the restaurant, when a suspect came up from behind him and stabbed him.
The suspect "casually exited the restaurant" before making his way toward a townhouse complex on Britannia Road.
Police say they are still analyzing video of the incident that was captured at the restaurant.
On Sunday, police issued a description of the suspect.
The suspect is a 5'5" with a medium build. Police say he has "sunken eyes," dark hair and appears to be in his early 30s. He wore a dark puffy jacket and a hat.
Anyone with information is asked to contact investigators at 905-453-2121, ext. 1133.
Information can also be passed on anonymously through Crime Stoppers at 1-800-222-8477.