Toronto police released a grainy security camera image of the suspect, where a long, white cloth is covering his face.
A 10th person has come forward to report a sexual assault that occurred near Bloor and Christie Streets, Toronto police say.
The woman filed a report earlier this week for an assault that took place on Aug. 27. As in previous attacks in the area, the woman reported being approached from behind and sexually assaulted, Constable Wendy Drummond said.
"We can't get into what actually occurred," Constable Drummond said. "But again, it's from behind, it's a brief encounter of a sexual assault."
The attacker fled on foot after the assault, she said.
Police describe the assailant as a black man of medium to heavy build, between the ages of 20 and 30. It was not clear whether he lives in the same Toronto neighbourhood where the assaults occurred.
"The fact that [the assaults are] all happening in the same area, at the same time, would lead one to believe the person has some ties to the area," Constable Drummond said.
Most of the attacks in the west Toronto neighbourhood took place over the span of about two weeks in late August, she said. No assaults are known to have occurred in September.
Earlier this month, hundreds of people gathered at Christie Pits park for an evening rally condemning the string of sexual assaults in the area. Participants marched through downtown Toronto bearing signs and several politicians and activists spoke to the crowd.
The rally was organized shortly after Mayor Rob Ford's niece, Krista Ford, wrote on Twitter that women worried about sexual assault shouldn't "dress like a whore." The tweet sparked outrage and prompted one woman who was assaulted in the Bloor and Christie neighbourhood to come forward with her story.