A 34-year-old former Janesville man is charged in Rock County Court with four counts of possession of child pornography.

According to the criminal complaint, the Rock County Sheriff’s Office received a tip from the National Center for Missing and Exploited Children in June about 11 videos of child sexual assault materials that were uploaded to a messaging app from an IP address in Janesville registered to David T. Neumann.

A detective reviewed some of the materials and found at least four videos that contained children engaged in sexual activity with adults.

Rock County Judge Jeffrey Kuglitsch issued an arrest warrant for Neumann, who lists a Sauk City address, on Tuesday.