Ottawa police have laid 24 more charges, for a total of 27, against a man alleged to have pulled down women's pants throughout the city over the past month.

Gavin Sean Griffiths, 25, is now facing 27 charges in connection with a series of alleged sexual assaults in Ottawa since April 14. (Facebook)

Gavin Sean Griffiths, 25, had earlier been charged with one count of sexual assault, one count of mischief and one breach of probation in connection with an incident that occurred on April 16, near Loretta Street and Young Street.

The new charges announced Friday include seven counts of sexual assault, eight counts of mischief, eight counts of breach of probation and one count of criminal harassment.

Griffiths is next scheduled to appear in court on Tuesday. He was arrested Wednesday evening while he was riding a bus in the city's west end.

OC Transpo video helped officers

The arrest came after a series of incidents that occurred between April 14 and May 7 in which women reported a man approaching them from behind and pulling their pants down.

Police had released a composite sketch of the suspect and asked the public for help in apprehending him.

Excerpts of video from OC Transpo surveillance cameras were given to officers across the entire police force. Griffiths was identified by officers on surveillance who then followed him to his home. He was then put on 24-hour surveillance until the arrest was made.

Insp. John Maxwell, who oversees major case investiagtions for Ottawa police, told CBC News that pure detective work led to Wednesday's arrest. (CBC)

"Most of us are husbands or fathers of daughters, and we knew the community was quite upset about it, as they should be," Insp. John Maxwell told CBC News Friday.

"Some surveillance officers … were working on something that was totally unrelated, spotted a male that looked to them like the person in the screenshots, followed him, and the rest was just pure detective work."

Griffiths had a prior record, but no prior sexual assaults, said Maxwell.

Friend, ex-girlfriend 'sick' over the news

Outside police headquarters Friday, Griffiths's ex-girlfriend Charlene Lafleur was sobbing.

"It makes me sick to my … stomach," she said.

His arrest also came as a shock to friend Shawn Lafleur, Charlene's brother, who said Griffiths was "a great guy" despite past troubles with the law.

"He's been blamed for many things before, ever since he's been in Ottawa he's been getting arrested for nothing, absolutely nothing," Lafleur told CBC News Thursday. "And now this. It makes me sick."