Toronto police have released surveillance video of a man suspected of sexually assaulting a woman in her apartment building.

In a news conference Monday, Det. Sgt. Joanne Rudnick said the victim, a 52-yeard-old woman, found a man loitering in the basement of her apartment building near Parliament St. and Bloor St. E. around 10:30 p.m. Saturday.

He followed her into the elevator and, brandishing a small handgun, forced her out of the elevator and into a stairwell, where she was sexually assaulted.

The man then fled the building through the lobby.

Police describe the man as black, 20 to 25 years old, five-foot-nine with a medium build. He was wearing a dark toque, grey hoodie, grey vest, black jeans and tan shoes. He had some facial hair, and was carrying a red knapsack.

Rudnick said a man with a similar description was seen loitering in a building near Isabella St. and Jarvis St. around 2 p.m. Sunday.

“I would ask members of the public who reside in the downtown area to pay special attention to anyone matching this description, loitering in apartment buildings or in stairwells,” Rudnick said.

Toronto police have now posted surveillance footage on Youtube that shows the suspect in the building’s basement and, later, leaving through the lobby.