MINNEAPOLIS (WCCO) — A former middle school band teacher has been charged with criminal sexual conduct after it was discovered he had been engaging in sexual behavior with a 15-year-old student.

According to the complaint, Howard Lake Waverly Winstead High School Principal Jason Mix reported to police Sept. 11 that the victim admitted to kissing Andrew Rosevold, 30, and to carrying on a conversation over Snapchat for several weeks. Mix said the victim told him the sexual activity began at the school and was mutual.

Police obtained the victim’s phone with permission from her parents and found the victim had saved her conversations on Snapchat. Police determined the messages were flirtatious and sexual in nature.

Authorities also discovered messages from Rosevold that directed the victim to “say we never did anything inappropriate” and “only my trying to help you with school, friends, homework, etc.”

Police executed a search warrant at Rosevold’s Elk River home on Sept. 18 where they found a USB drive in his bedroom containing videos showing body parts of several other underage girls. Four of the videos showed Rosevold and the victim kissing, hugging and touching. They all appeared to have been taken at the Howard Lake school.

Superintendent Brad Sellner released the following statement:

“The School District was made aware that criminal charges were filed against Andrew Rosevold, who recently resigned his position as the School District’s Middle School Band Instructor. We take the safety and security of our students very seriously and are cooperating fully with law enforcement in its investigation.”

Rosevold has been charged with four felony counts of criminal sexual conduct and is currently in custody in Wright County.