Ottawa police are investigating another brazen sexual attack in the capital, the eighth one in recent weeks.

Police say an 18-year-old woman's pants were pulled down around noon on Monday at the Lincoln Fields transit station.

She was walking along a pathway leading to the transit way when a man approached her from behind and tried pulling down her pants.

The woman turned around and threw coffee in the suspect's face before he walked away.

This latest attack has some female transit riders on the lookout.

"Even during the day he's doing it, so you're not really safe anywhere you go," said Amanda Makort. "But it makes me nervous, its eight attacks now?"

Several of the assaults have happened near transit hubs, with the latest one occurring at a transit station. That has OC Transpo constables on high alert.

"We are now talking about three different areas of the city. Frankly it can happen anywhere," said Sergeant John McGetrick of the Ottawa police sex assault unit.

The suspect is described as a white man, 20 years old, five-foot-six with short dark hair and a goatee. He was wearing a black baseball cap, jeans and a black sweater.

Five previous attacks happened in the downtown Ottawa area. Two others occurred in Alta Vista. In each case, women were approached from behind, their pants were pulled down, and in some cases they were inappropriately touched.

In another incident, a man followed a women from a transit station into a south Ottawa school.

The string of attacks has left many women in the city shaken.

"It's a bit alarming," said one woman. "You want to be able to catch the bus safely but at the same time keep your eyes open."

Police emphasize women should be cautious at all times, not only near transit hubs.

As long as the predator is on the loose, some women say they'll take extra precautions.

"Maybe I'll wear jeans from now on, not loose pants," said Crystalena Paquette. "It's easier to pull down pajama pants than jeans."

Police previously released a suspect sketch, which has led to dozens of tips. Anyone with information is asked to contact the Ottawa Police Sexual Assault/Child Abuse Section at 613-236-1222 ext. 5944 or Crime Stoppers at 613-233-8477 (TIPS).

With files from CTV's John Hua.