COLUMBIA — A coach at a Chesterfield County high school sexually abused two middle school students in Oconee County more than a decade ago, authorities said.

Richard Gardner III, 39, was arrested Thursday and charged with 11 counts of criminal sexual conduct with a minor, and 13 counts of lewd act on a minor, Oconee County deputies said.

An investigation began earlier this month when deputies received a report that Gardner might have abused students while working as a teacher at Walhalla Middle School and a wrestling coach at Walhalla High School. The abuse occurred at his home and at school between 1998 and 2003, authorities said.

Deputies said they identified two victims, ages 12 and 14, but have evidence that shows more children may have been abused.

The Oconee County Sheriff’s Office didn’t respond to a request for more information about the charges against Gardner.

A phone listing for Gardner could not be found, and it wasn’t clear whether he had a lawyer. He is being held at the Oconee County jail on a $730,000 bond.

Gardner was arrested Thursday at Pageland Central High School and was placed on administrative leave. He has worked at two schools in the Chesterfield County School District since 2005, district spokesman Ken Buck said.

Gardner lives in Kershaw, and Lancaster County deputies helped search his home and a second property he owns, sheriff’s spokesman Maj. Matt Shaw said.

Shaw wouldn’t talk about what was found, but he did say deputies in his county also investigating are Gardner.