The Toronto police sex crimes unit is now helping to investigate the violent assault of two women as they stepped off a TTC bus.

Investigators with the sex crimes unit said at a news conference Wednesday that the aggressive nature of the attacks was a source of concern.

"The behaviour demonstrated by the offender is a great concern and has resulted in the co-ordination of efforts from the field units, the sex crimes unit (and the) TTC," said Det. Tom Lynch.

The women were not sexually assaulted but they were both violently grabbed from behind and thrown to the ground.

The first incident happened on Sept. 25 when a 24-year-old woman was followed off the Yonge subway and onto the Cummer Avenue bus. When she stepped off, a man followed her, shoved her to the ground and yelled at her to "shut up" before stealing her purse and running away.

The second incident happened on Oct. 14 when a 29-year-old woman stepped off a bus on Pape Avenue. She told police she noticed that a man had followed her from the subway and onto the bus. Once they were on the bus, he stared at her and made her feel uncomfortable, an officer on the case told last week.

Minutes after stepping off the bus, the woman was shoved to the ground. She wasn't robbed and the culprit fled the scene.

Police say they are looking for a suspect who is white, about 30 years old, with a shaved head and a pot belly. He wears an earring in his left ear.

Anyone with information is being asked to call police at 416-808-5400. Anonymous tips can be left with Crime Stoppers at 416-222-TIPS.