Authorities fear Jean-François Lussier may be violent.Authorities fear Jean-François Lussier may be violent. (Courtesy of Quebec provincial police)Quebec police are looking for a escaped psychiatric institution patient whom they fear may lash out.

Jean-François Lussier, 30, broke a second-floor window and climbed out of the Philippe-Pinel Institute in Montreal early Wednesday.

Lussier has been detained at the full-security psychiatric institution since Aug. 31, after he was arrested for a series of violent crimes. He was not held criminally responsible because of mental illness.

Police believe Lussier could commit another crime while he's on the lam.

The 30-year-old wasn't wearing winter clothes when he escaped.

Authorities at the institute said he was dressed in a blue sweatshirt and sweatpants.

Lussier is about five-foot-seven and weighs about 165 pounds. He has sandy blond hair and blue-green eyes.

Police are asking people with information on Lussier's whereabouts to call toll free 1-800-659-4264.

With files from The Canadian Press