The article in question did not really make it clear which party was "foaming at the mouth".What it did say was that the "suspect" stopped his car,rolled down his window,showed his driver's license,engaged in conversation,but was uncooperative!
'Uncooperative! I guess that is one way of saying that he fled from the traffic stop, which is a felony. When he was pursued, and stopped again, he was witnessed pulling a weapon. He then fled again, and when he was stopped the last time, he left the car firing his weapon, killing a local cop, leaving a widow and children. I guess that you can call this uncooperative! Wonder why you left this part out?