A federal judge has sentenced a 25-year-old man to 21 months in prison for a 2010 sexual assault in Hawaii Volcanoes National Park, the National Park Service said in a news release.

U.S. District Judge J. Michael Seabright also sentenced Jeffrey Donald Drye last on Nov. 3 to one year of supervised release and a lifetime requirement to register as a sex offender with the state of Hawaii.

A federal jury convicted Drye on June 20 of abusive sexual contact, but found him not guilty of first-degree sexual assault.

The park service said the incident happened on Jan. 30, 2010, when Drye, two other adult males and a minor girl hiked into Volcanoes National Park’s Kahuku unit at night. The group made a campfire, during which time two men returned to their vehicle about one mile away to retrieve food, leaving Drye alone with the girl. That is when the sexual assault took place, the park service said.