TABOR, S.D. (KELO) — A Tabor, South Dakota man is facing a felony drug charge after his mother unknowingly served his marijuana-laced brownies to a group of senior citizens.

The investigation started after Bon Homme County dispatchers received several calls about possible poisonings.

All the calls involved people had been at a card game earlier that night. The brownies were tracked back to Michael Koranda.

At the time of the incident, Koranda was a teacher in the Bon Homme School District.

In court papers, Koranda told authorities he had recently brought THC butter back from Colorado and used it in the brownies…. and that his mother didn’t know that.