At this point, a single county sheriff could have showed up and probably would have been able to serve the warrant peaceably. However, the ATF showed up looking like Patton's Third Army and leaked word of the coming raid to the press, which in turn (inadvertently) tipped off the Branch Davidians. This did not put Koresh and company in a reasonable state of mind. No one knows who fired the first shot, and as Bubba Clinton pointed out later with some heat, you're not entitled to shoot law-enforcement officers who are trying to serve a warrant on you, but on the other hand, it's hard to see how ATF could have handled it more poorly. Then ensued a siege.