Toronto police are warning women to be on the lookout for a sex assault suspect who approached a woman by telling her he needed help on a school photography project.

Police say a man who appears to be in his 40s approached a woman in her 20s last week as she was leaving a coffee shop and asked to take her picture for a school project.

The suspect identified himself as "Steve" and told the woman he is a student at Ryerson University working on a photographic collage.

The woman was led into a laneway in the Bloor Street and Madison Avenue area where the suspect began to take pictures of her. He then asked the victim to start exposing herself more to him, police say.

Det. Rob Ermacora, of Toronto police 53 Division, said at that point the victim was sexually assaulted.

The attack was brazen, happening at around 10 a.m. on Thursday, April 3.

Ermacora said he's concerned there could be more victims out there.

 "There had obviously been some preparing done before he approached the victim," he told CTV.ca.

The suspect is described as a white male with short, curly, dark, graying hair, clean-shaven with a thin build. He stands at about 5'7 and was wearing blue jeans, a blue jean jacket and tinted sunglasses. He was carrying a black backpack which contained a camera with lens.

This isn't the first time the area has been put on alert for sex offenders.

In January, police issued a warning about a peeping Tom seen lurking around windows.

There are a high concentration of student residences and a high volume of university students in the neighbourhood, Ermacora said.

Police have stepped up patrol in the area and have tried to educate the public with safety tips, he said.

"The problem is it's random, (the perpetrators) come and then disappear," he said. "It's like looking for a needle in a haystack.

"The best thing we can say to the public is to have a safety plan and go with your intuition," he said. "If your intuition is telling you something isn't right then don't do it."

He also said people should try their best to remember details about the suspect such as his physical appearance and other identifying factors.