Lieutenant Joel Haasterman was a member of the American military.
He was attempting to deal with the aftermath of The Golgotha Project, unwillingly getting help from whom he thought was Aleister Crowley. When the Fourth Doctor and Romana escaped, though, Crowley dropped his human guise in frustration, revealing himself to be a Jarakabeth. He changed the nearby troopers into monsters and since the transformation made them hungry, he had them eat Haasterman. (PROSE: Heart of TARDIS)