Butch is one of two paranoid militiamen who hold Chakotay and Torres captive in the Arizona desert in Future's End, Part II, believing them to be agents of the United States government.
Butch appears in Future's End, Part II, from Voyager's third season. He and his companion Porter live in an isolated compound in Arizona, armed to the teeth and convinced the federal authorities are coming for them.
When a Starfleet shuttle falls out of the sky nearby, they drag its two occupants inside and tie them up. Butch is the more practical and menacing of the two, less inclined to speeches than Porter and more inclined to reach for a rifle.
When what they take for a government raid begins outside, the pair open fire, only to see their bullets pass straight through the Doctor, who has a mobile emitter and no fear of injury. Tuvok and the Doctor free the prisoners and leave the two men to make of it what they will.