A daylong manhunt in suburban Boston ended Sunday in the shooting death of a suspect found holed up after police say he killed an officer during a routine traffic stop. Auburn, Massachusetts, Officer Ronald Tarentino, 42, was shot and killed at 12:30 a.m. Sunday, by a gunman who fled the scene. By evening, law-enforcement authorities said they had tracked the suspected gunman, Jorge Zambrano, 35, to a duplex five miles from the crime scene. Inside, Zambrano reportedly burst from a bedroom closet to shoot at officers, who returned fire; he was later pronounced dead at a local hospital. Investigators said they where looking into what triggered the initial traffic stop, though Zambrano reportedly had a long criminal history and spent time in a state prison.