BISBEE, Ariz. (AP) A Maine National Guard soldier has been charged with sexually abusing a colleague while serving on the southern border, officials said.

Bret Chapman, of Walpole, Maine, was charged with kidnapping, two counts of sexual abuse and one count of aggravated assault, Michael Powell, deputy attorney for Arizona’s Cochise County, said Friday.

The assault took place in December while the Maine National Guard were deployed in Arizona, he said.

Chapman was arrested on Aug. 27 and posted bail. It’s unclear if a public defender has been appointed for him, Powell said. Chapman didn’t immediately return an email from The Associated Press seeking comment.

The Maine National Guard, which is aware of the charges, said it couldn’t discuss specifics, but it encouraged soldiers to report such behavior.

“Sexual assault and all forms of harassment are repugnant and beyond unacceptable — they stand in stark opposition to Army values and what it means to wear our nation’s uniform. We actively encourage reporting incidents and commend those who do,” said Maj. Carl Lamb.

It’s unclear why it took so many months to bring charges, but the decision was ultimately made to seek an indictment in Cochise County, Powell said.

The 262nd Engineer Company deployed to the southern border in October to assist U.S. Customs and Border Patrol. It’s due to return this fall.