ACHILLE, Okla. (AP) — Officials closed a rural Oklahoma school system this week after the sheriff began investigating what he determined were online threats against a transgender student.

Bryan County Sheriff Johnny Christian said Tuesday his office started investigating over the weekend after adults made threatening comments on Facebook about a 12-year-old transgender girl using a public girls' bathroom at Achille Public Schools, about 160 miles southeast of Oklahoma City and near the Texas border.

School officials arranged for the student to use a staff bathroom when she was in elementary sc...