inputs: hypothesis: Margaret is the mother of Richard Poplawski. premise: A 911 call that brought two police officers to a home where they were ambushed, and where a third was also later killed during a four-hour siege, was precipitated by a fight between the gunman and his mother over a dog urinating in the house. The Saturday argument between Margaret and Richard Poplawski escalated to the point that she threatened to kick him out and she called police to do it, according to a 12-page criminal complaint and affidavit filed late Saturday. When officers Paul Sciullo and Stephen Mayhle arrived, Margaret Poplawski opened the door and told them to come in and take her 23-year-old son, apparently unaware he was standing behind her with a rifle, the affidavit said. Hearing gunshots, she spun around to see her son with the gun and ran to the basement. "What the hell have you done?" she shouted.