Investigators are searching for a suspect after police say a 26-year-old woman fell asleep on a GO bus and was sexually assaulted.

At around 4:30 p.m. on April 4, a 26-year-old woman was on board a southbound GO bus on the Don Valley Parkway.

At some point during the ride, the woman fell asleep and that’s when investigators allege she was sexually assaulted by a man seated in front of her.

Police say the woman woke up in the middle of the assault.

The man was seen getting off the bus at the Union Station bus terminal.

The suspect has been described as 45 to 55 years old and is about five-foot-eight to five-foot-ten. He reportedly has a larger build, greyish hair, and was clean shaven. He was seen wearing a black baseball hat with white writing on the front and a burgundy or reddish hoodie, a black leather jacket, black pants and flat shoes.

Anyone with information about the suspect is asked to call police at 416-808-5200 or Crime Stoppers anonymously at 416-222-TIPS (8477).