Authorities said 30 iPads owned by Columbia Public Schools were being held as evidence by law enforcement in various investigations.
The Columbia Daily Tribune reported that 10 iPads were in the possession of the Boone County Sheriff's Department and 20 were with Columbia police.
Boone County Sheriff's Department Detective Tracy Perkins said a majority of the devices were used to share sexually graphic conversations or videos. Perkins said one investigation involved a school district employee, and the rest involve students, either as a victim or suspect.
The school district owns 12,000 iPads that were provided to all classroom teachers, fifth- and sixth-graders, and students in Advanced Placement courses and Battle High School students.
District spokeswoman Michelle Baumstark said not all of the iPads held as evidence are from investigations that started this school year.