SIOUX FALLS, S.D. (KELO) — A former South Dakota teacher could be headed to federal prison.

33-year old Charles Reambonanza pleaded guilty to having child pornography Monday. He used PayPal and an app to buy the illegal images from someone in the Philippines.

Before his arrest, Reambonanza was a science teacher at St. Francis Indian School. The school suspended him after learning about the allegations.

When he’s sentenced, he faces a minimum of five years of supervised release and a maximum of 20 years in federal prison.