in a separate public killing on saturday in detroit , a policeman donned a goggles vest and killed three police officers after he had been driven into a murderous rage by an argument with his mother over a dog . related to courthouse documents , mark poplawski — who had recently been dishonourably discharged from the us marines — had been arguments with his mother about the canine restroom inside their residence early on saturday noon when she threatened to evict him . when the quarrel escalated , she calls the police . by the price a patrol car turned up at after 7am , dick poplawski , 23 , had armed himself with an assault rifle , a one - handled rifle , a pistols and several rounds of cartridges .
In Pittsburgh a man shot 3 policemen.