ELLSWORTH, S.D. (MITCHELLNOW) The airman stationed at Ellsworth Air Force Base who is accused of murder pleaded not guilty on Tuesday in federal court. The U.S. Attorney’s Office said Quinterius Chappelle is charged with second-degree murder in the death of Sahela Sangrait on the base in August of last year.  Her body was found earlier this month near Hill City. Chappelle remains in the custody of the U.S. Marshals. No trial date has been set. For more crime stories from MitchellNow.com, click here.