I just seen something on Live PD that amazed me. That K9 cop let his dog go on it's own to bring down a runner, the cop was alone and had 2 guys bail on him. He took 1 down and let the dog go after the other, the handler lost sight of his dog as the dog chased the guy into some woods. The handler could hear the dog whimpering....so he made the subject in custody run with him and they found the dog. That dog had the 2nd guy, or the guy had the dog. That guy had grabbed the K9 by the collar and the dog couldn't do anything. I expected the guy to be torn up, but he didn't get a scratch. I was surprised he was able to do that and kind of shocked they showed it on TV. That dog was stuck and very vulnerable, easy way to get em shot or stabbed....can a K9 go without a collar or is it mandatory?