When they arrived at the Bonis Avenue building on Saturday morning, they were directed to a man who was "sitting in the library holding a cucumber," according to a news release.
Police say the man was allegedly recognized from an incident that occurred at the same library in April.
It is alleged that on the evening of April 7, a man approached a woman, sat down next to her and opened a laptop computer. Police say the man "then began to commit an indecent act while holding a cucumber."
Fredrick Tennyson Davis, 49, has been charged with an indecent act count and two counts of fail to comply with probation.
Police have released an image of Davis. They believe there could be other victims.
Anyone with information is asked to contact investigators at 416-808-4200. Tips can also be passed on anonymously through Crime Stoppers at 416-222-8477.