Montana schoolteacher Sherry Arnold, missing since Saturday, has been found dead, according to a posting on the Sidney Public Schools website.
The school district provided no other information.
Law enforcement officers have taken "one adult male into custody, and another adult male is being questioned" in relation to Arnold's case, the FBI said Friday in a statement.
The 43-year-old schoolteacher was last seen out on a morning jog through her small town.
One of her running shoes was found along her route, but authorities indicated there had not been any other sign of Arnold.
Sidney police Chief Frank DiFonzo said earlier this week that teams had been using dogs and aircraft to search for Arnold and have gotten help from National Guard members as well as volunteers.
On Thursday, the FBI put out a poster of Arnold and added her to its "kidnapping and missing persons" website.
Arnold's disappearance has hit the small community hard, including at Sidney High School, where she is a math teacher. Situated near North Dakota and about 100 miles south of the Canadian border, Sidney has a population of just under 5,200 people, according to the U.S. Census Bureau.