A Chicago man was sentenced Friday to 22 years in federal prison for secretly recording boys changing in three Chicago-area YMCA locker rooms and possessing nearly 100,000 pictures and videos depicting child pornography.

Michael Porter, 58, pleaded guilty last year to charges of production, receipt and possession of child pornography.

For about 20 years, authorities said, he had recorded young boys with a camera he hid in a bag and “strategically” placed in YMCA changing and shower areas.

Authorities said they found Porter possessed more than 46,500 images and 44,500 videos of child pornography — including “sadistic” and “masochistic” acts. 

A judge ordered Porter to pay $63,500 in restitution to his victims, in part to help pay for some of the victims to attend schools for victims of abuse. The 10 victims in the case are to receive between $5,000 and $10,000 each.

“Michael Porter was a prolific manufacturer and collector of child pornography,” Assistant U.S. Attorneys Kristen Totten and Elly M. Peirson wrote. “The victims will live with the trauma imposed upon them by the defendant for the rest of their lives.”