Jason R. Alsteen, 35, of Wausau. Felony charges filed May 24 include 20 counts of possession of child pornography.

WAUSAU — A 35-year-old Wausau man who downloaded hundreds of images of child pornography and shared them with others will spend five years in prison.

Jason R. Alsteen was convicted Oct. 27 on 10 counts of possession of child pornography, charges that were first filed May 24 in Marathon County Circuit Court. As part of a plea deal with prosecutors, 10 additional charges were dismissed.

A year-long investigation revealed Alsteen had at least 252 files of child pornography on his computer, some of which showed images of toddlers being sexually assaulted by adult men, according to the criminal complaint. The videos and photos were being shared through a peer to peer file sharing network.

The investigation was first launched in May 2016, when police traced the images to an IP address at a home where Alsteen was living. In July 2016, police searched the home, where they found the computers storing and sharing the files.

Alsteen initially denied having any child pornography on his computer, then said the images were accidentally downloaded, according to the police report. But investigators said the images were downloaded using defined search terms, then were placed into a folder for sharing with other users around the world.

Alsteen faced a maximum of 500 years in prison, but instead will spend five years behind bars. Marathon County Circuit Judge LaMont Jacobson also ordered Alsteen to spend an additional five years on extended supervision after his release, and be listed on the sex offender registry for an additional 15 years after his supervision ends.