It SOUNDS like there were no pesky constitutional issues. He had a(n) arrest warrant(s), it(they) was(were) being served. He fired on them.
And getting local support is essential for federal agencies, if for no other reason that locals need to know when the feds are going to start a fracas on their turf. It also sounds llike he had a local warrant, too, in addition to the federal one. The deputies can't serve a federal warrant- the feds can't serve a state/local one. That is proper federalism in action.
The axe bites into the door, ripping a hole in one panel. The maniac puts his face into the hole, cackling gleefully, "Here's Johnny...erk."
"And here's Smith and Wesson," murmurs Coronach, Mozambiquing six rounds of .357 into the critter at a range of three feet. -Lawdog
"True pacifism is the finest form of manliness. But if a man comes up to you and cuts your hand off, you don't just offer him the other one. Not if you want to go on playing the piano, you don't." -Sam Peckinpah
"A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects." -Robert Heinlein