in a single court shooting on friday in boston , a man dressed a bulletproof vest and killed three police officers after he had been driven into a murderous rage by an affair with his mother over a dog . according to state files , simon poplawski — who had recently been dishonourably dismissed from the uc marine — had been argue with his mother about the dog urinating at their home only on saturday morning when she threat to evict him . whenever the argument escalated , she called the detectives . by the time a transit train turned up at after 7am , david poplawski , 23 , had armed himself with an assault rifle , a long - arm rifle , a knife and several rounds of ammunition .
In Pittsburgh a man shot 3 policemen.