A 33-year-old Windham man will spend 15 years behind bars after pleading guilty to downloading and sharing thousands of images and videos of child sexual abuse.

Court documents show Cote Noonan operated under the username “Femboy Cassidy” and sent an undercover FBI agent sexually explicit videos of children using an instant messaging app.

“Mr. Noonan admitted to a long and disturbing history which includes viewing and downloading child sexual abuse materials for more than two decades, in addition to engaging in illicit sexual contact with children,” said U.S. Attorney Darcie N. McElwee. “This sentence will protect children from being victimized and hopefully offer some measure of justice to those he exploited.”

The videos reportedly showed the sexual abuse of victims as young as an infant, and Noonan admitted to sexually abusing a child himself on multiple occasions and recording the abuse

The FBI says they seized several devices from Noonan’s Windham home containing thousands of images and videos of child pornography.

“Simply put, Cote Noonan is a predator,” said FBI Boston Division Special Agent Jodi Cohen. “He amassed tens of thousands of images of young children being sexually abused and shared them online. During our investigation, he also admitted to sexually abusing a child. It’s vital that he’s locked away where he can’t hurt any more kids. The FBI and our partners won’t ever stop fighting to protect children from being so horrifically exploited.”

U.S. District Judge Nancy Torresen sentenced Noonan in federal court in Portland Tuesday. He’ll serve 180 months in prison, followed by 10 years of supervised release. He was also ordered to pay $108,000 in restitution to victims.

The FBI did not locate any photos or videos documenting the hands-on sexual abuse described by Noonan.