A suspicious death in Waterloo has been ruled a homicide. An autopsy confirmed what police believed — that 45-year old Randy Manning had been stabbed to death. Manning’s body was found Tuesday night inside the two-story home that he shared with his brother on the city’s east side. Police labeled Manning’s death suspicious after finding a stab wound in his upper torso. The victim’s brother, 52-year old Anthony Manning, who lives at that same address, was arrested on an unrelated charge. Authorities aren’t saying if he’s a suspect in the murder. The case remains under investigation.