in a separate mass shooting on saturday in pennsylvania , a man donned a bulletproof mask and killed three police officers after he had been drove into a murderous argument by an argument with his dad over a dog . per to court papers , joseph poplawski — who had recently been dishonourably suspended from the uk marines — had been upset with his grandmother about the dog urinating behind their property early on saturday eve when she came to evict him . when the violence escalated , she calls the police . by the time a service truck turned up at after 7am , mr poplawski , 23 , had armed himself with an assault vest , a long - arm revolver , a revolver and several rounds of rounds .
In Pittsburgh a man shot 3 policemen.