in a related mass shootout on saturday in pittsburgh , a man donned a bulletproof vest and killed three police officers after he had been driven into a murderous rage by an argument with his mother over a dog . due to courts papers , richard poplawski — 24 had recently been dishonourably received from the us troops — had been arguing with his mother about the dog urinating inside their apartment early on tuesday morning when she promised to evict him . because the argument began , she called the police . by the time a police truck turned up at after 7am , mr poplawski , 23 , had armed himself with an assault rifle , a long - shoulder rifle , a pistol and several rounds of ammunition .
In Pittsburgh a man shot 3 policemen.