in a separate mass shooting on saturday in pittsburgh , a man donned a bulletproof vest and killed three police deputies after he had been drove into a murderous rage by an argument with his mother over a dog . according to court papers , richard poplawski — who had recently been dishonourably discharged from the us marines — had been arguing with his mother about the canine urinating inside their yard early on saturday morning when she threatened to evict him . during the argument ensued , she contacted the ambulance . by the time a patrol car showed up at after 7am , mr poplawski , 23 , had equipped himself with an electric weapon , a long - arm rifle , a revolver and several round of ammunition .
In Pittsburgh a man shot 3 policemen.