Investigators are searching for a suspect after a woman was followed for two hours on the rail trail Wednesday by a man on a bike who at one point was masturbating, police say.

The woman was jogging on the rail trail in the area between Limeridge Road and Mount Albion Road when she first noticed a man who appeared to be following her.

"She indicates over the course of approximately two hours, the male would follow her while on his bike, at one point she turned around and saw the male clearly masturbating with his genitals exposed," a police news release reads.

The woman asked him if he was following her. He replied "no," police say, but then continued to follow her.

He was last seen near the Kenilworth stairs at Kimberly Drive. Police walked part of the rail trail in the area, but didn't find anyone matching the suspect description.

The man is described as white and in his 20s, about five foot six inches tall, with short red hair and partially scruffy facial hair.

He was wearing a green t-shirt, black track pants and a green/brown camouflage backpack.

He was riding a red bike with the word "Triumph" written along the frame in black and white.

Anyone with information is asked to call police at 905-546-2907 or Crime Stoppers at 1-800-222-8477.