BILLINGS, Mont. (AP) — An assistant police chief says what is believed to be the body of a missing Montana school teacher is being sent to the state medical lab for further identification.Forty-three-year-old Sherry Arnold, of Sidney, disappeared Jan. 7 during a morning run.Authorities say they started recovery efforts Monday about 50 miles away near Williston, N.D., and found the body Wednesday. They say it had been buried.It's still not clear what led them to that location.Twenty-two-year-old Michael Keith Spell and 47-year-old Lester Van Waters Jr., both of Parachute, Colo., pleaded not guilty last month to one count each of aggravated kidnapping.They could face the death penalty if convicted.