01/15/2013 03:56 EST | Updated 03/17/2013 05:12 EDT

Police seek help in nabbing long-time sexual assault suspect

Montreal police are looking for help in finding a man suspected of being involved in several sexual assault cases.

According to a news release, the man is Caucasian, between 40 and 50 years old. He is approximately five foot nine inches tall and speaks French.

He sometimes wears glasses and a short black jacket with blue jeans.

Police say an investigation has allowed them to link the suspect to several incidents that took place between 2006 and 2012 in Ahuntsic-Cartierville, Rosemont and the Hochelaga-Maisonneuve neighbourhoods.

They say the man always attacks women from behind and places his hand on their mouths. Most of the attacks took place at night.

In some cases, police said the man used a knife to threaten his victims.