Mrs. McBain was a resident of Primm, wife to Sheriff McBain, and Beagle's sister. Poor Mrs McBain was killed and decapitated by the escaped convicts about a month before the Courier is ambushed at Goodsprings. Their rotting remains were left behind at the deserted office. Their remains are buried by the townsfolk once the player restores peace.
Mrs. McBain appears only in Fallout: New Vegas.