Longueuil police are stepping up their search for a suspect they believe is responsible for a series of sexual assaults in the Brossard area.

Officers are asking for the public's help to find a man who they suspect is responsible for 11 different sexual assaults.

Police said the most recent incident was on Dec. 8, 2012, at about 7:30 p.m. Officers said the alleged victim, an 18-year-old woman, was on the bike path in Brossard, near the intersection of Rome and Milan boulevards when she was assaulted.

According to police, the alleged assaulter was in possession of what appeared to be a handgun at the time.

The same suspect is believed to have committed 10 sexual assaults dating back to 2010. In those incidents, police say he often threatened his victim with a knife.

No arrests have been made.

Longueuil police Const. Mark David said the suspect has targeted women between the ages of 15 and 25 years old.

"[In] most of the cases, we believeĀ  he would have followed the victim from the Panama bus terminal," David said. "In this last case in December, the ... young woman was getting off the 41 bus."

The suspect is in his thirties, weighs approximately 169 pounds and measures about 6 feet tall.

He has brown hair, and speaks English and French.

Investigators will have a command post set up on Thursday evening between 5 p.m. and 9 p.m. at the public transit Brossard-Panama terminal in Brossard.

Anyone with information about this incident is asked to contact investigators at the command post, or call 450-463-7211.

Police are also advising women walking alone in the area to stay in well-lit areas, be wary of suspicious-looking people and avoid using electronic devices like cell phones or earphones that could prevent them from hearing what is going on around them.