A 14-year-old girl was walking south from Cassandra Boulevard on Welsford Gardens at about 8:30 a.m on Thursday when, according to investigators, she was approached from behind by an unknown man.
The man allegedly placed his arm on her shoulder and threatened to hurt her if she tried to escape. They walked southbound, side by side, before he sexually assaulted her.
Police say the man let the girl go before reaching Rowena Drive and fled westbound between a row of townhouses.
Investigators released a composite sketch of the suspect on Monday.
He is described as black, in his early 20s, about six feet tall with a medium build, braided hair and a thin moustache. He was wearing a baggy, long, grey sweater, a baseball cap worn backwards and blue jeans.
Anyone with information is asked to contact 33 Division at 416-808-3300, reach Crime Stoppers online or call 416-222-TIPS.