A former Owsley County school volunteer admitted receiving text messages from a 13-year-old girl that contained sexually explicit images.
Dominic Johnson faces a prison term of five to 20 years, according to the charge. He is to be sentenced in December.
Johnson pleaded guilty Monday. U.S. District Judge Gregory F. Van Tatenhove ordered him jailed pending sentencing.
Johnson's plea said he received the text messages in December 2012. The plea document said Johnson was a teacher at Owsley County Middle School and had established a relationship with the girl through his job.
Owsley County Superintendent Tim Bobrowski said Johnson was not a full-time teacher. Rather, he was on the list of substitute teachers and did volunteer work, Bobrowski said.
Bobrowski said the district had done a background check on Johnson, which showed no problems, before the incident.
Bobrowski said he learned of the alleged illegal texts after one of the photos briefly showed up on Facebook and a parent called him.
Bobrowski said he quickly notified state police and social workers, told Johnson he was under investigation and barred him from school grounds.
Johnson resigned, Bobrowski said.