MONTREAL - A woman whose son fought off a potential sexual assailant last winter has found some satisfaction.

The NDG mother recently came across a man who fit the description her 13-year-old son provided of the man who he said attacked him on the 24 bus in December.

The boy successfully fought off the assailant but the family remained deeply shaken by the experience and police had never come up with a suspect.

But recently the woman was walking near the Vendome metro and realized a certain person fit the description of her son's alleged attacker.

The man, in his 50s, had long hair, a black beard and wore a long black coat.

"It was a toss-up between taking his photo with my cell phone or calling 911 so I called 911 and I told them that this was the guy who assaulted my son and that I wanted police to come right away," the woman told CTV Montreal's Stephane Giroux.

"I kept following the guy, he crossed the street and kept walking and I kept on him until police arrived."

The woman phoned 911 and kept an eye on the man. Police arrived after a few minutes and detained the man.

The mother also called her son, who came and spied the person and who confirmed that it was his attacker.

The suspect was taken into custody and charged.

The suspect gave his address as a homeless shelter and appears to be a vagrant, possibly with mental difficulties.

His lawyer said that the 56-year-old suspect would require an assessment to determine his psychological state.

The woman's name cannot be published, but she was seen discussing the story with a wide range of friends on social media, clearly delighted that justice appears to have been served.