I'm guessing they weren't trying to kill it, just get it stopped from being a PIA, which it seems the succeeded in doing.
I'm betting there were 3 big dicks there, all measuring and shouting. I'm betting there was a rancher that wasn't accustomed to taking 'orders' from ANYONE and cops that weren't accustomed to someone NOT taking orders from them.
Seems it would have taken one level head to have fixed the situation, which there obviously wasn't, on either side.
What I'm certain of is that the rancher didn't walk up, say howdy boys and then the cops shot him for sheits and giggles.
Again, likely enough ego from all sides to fill a wagon, but of course the professionals are the ones that should be able to keep said egos checked.
It was obviously a cluster [bleep] of epic proportion. There should have been ONE calm head in charge of the scene. Maybe there was, maybe there wasn't.
