CASTLE ROCK, Wash. - A substitute high school teacher has been arrested in connection with explicit sexual text messages sent to a female student, police said.

Dustin Matthew King, 27, of Longview, Wash., was arrested Friday afternoon and booked into the Cowlitz County jail on suspicion of communication with a minor for immoral purposes. He posted bail and was released.

The text messages came to light after a fellow student at Castle Rock High School saw the explicit texts on the victim's phone and reported them to school staff, police said. Principal Jenny Risner called police, who investigated the incident.

King was working as a substitute at the high school. It was not clear if he has taught at other schools as well, said Sgt. Scott Neves, a Castle Rock police spokesman.

Police described the texts as "containing explicit sexual content." No more information on them was released.