GARDEN CITY, Kan. (AP) — Authorities have dismissed child pornography charges against a former teacher but the investigation is continuing.

Finney County authorities said Wednesday that three counts of sexual exploitation of a child filed in January against Steven Thompson were dismissed.

KAKE-TV reports assistant county attorney William Votypka says if the ongoing investigation discovers more evidence, authorities wouldn’t be able to pursue those charges if they are still prosecuting the original case.

The investigation began while Thompson while working at Garden City Community College. Authorities say they found child pornography on his work computer, another computer, and other devices.

Thompson was hired in April 2015 by the Wichita school district. His background check didn’t indicate his legal problems because he hadn’t been charged when he was hired in Wichita.