Toronto police are investigating an alleged sexual assault on a TTC bus on Thursday and have released a photo of the suspect.

Police say the woman was sitting on the bus, heading along Lawrence Avenue East, when a man sat down beside her around 12:30 a.m.

He sexually assaulted her, the woman told the driver and the man fled the bus.

The suspect is brown, 50 years old, five-feet-eight-inches tall and 200 pounds. He has grey/black short hair and a moustache. He was last seen wearing dark-coloured pants, a beige sweater over a collared dress shirt and dark shoes.