A New York State Police trooper was killed while responding to a domestic dispute involving a U.S. Army soldier in Theresa, N.Y., on Sunday night, the police said. The soldier’s wife was also killed, the police said. Trooper Joel R. Davis, 36, was shot as he approached the soldier’s residence, a statement from the state police said. The soldier, Justin D. Walters, 32, an active duty Army infantryman who is stationed at Fort Drum, was arrested. His wife, Nichole V.