A 26-year-old woman says she was sexually assaulted while asleep on a GO Transit bus in Toronto on April 4.

The woman told police she was travelling southbound on the Don Valley Parkway at around 4:30 p.m. when the incident took place.

It is alleged that the woman woke up while being sexually assaulted by a man sitting behind her on the bus.

After the alleged incident, the man remained on the bus and was last seen exiting the bus at Union Station.

The suspect has been described by police as a five-foot-eight to five-foot-10 man between the ages of 45 and 55 with a bigger build, greyish hair and was clean shaven. At the time, he was wearing a burgundy/reddish hood, a black jacket, black pants and flat shoes. As well, he was wearing a black baseball hat that had white writing on the front of it.

A security camera image of the suspect has been released by police in an effort to identify him.

Anyone with further information is asked to contact police at 416-808-5200 or Crime Stoppers anonymously at 416-222-TIPS (8477).