The "freemen" were afraid of being injected with cancer cells and "no brain" drugs in jail and were ready to shoot it out with federal agents at their Montana farm, according to recordings aired on "Dateline NBC."
Colorado state Sen. Charles Duke, who was invited by the freemen to negotiate during the 81-day standoff, taped his conversations with members of the group and provided some of the tapes to the Sunday TV show.
On the tapes, freeman Edwin Clark spoke of his fear he would be injected with cancer cells.
"When [freeman Leroy Schweitzer] went to Missouri, a man, a doctor from New York City, come in and told Leroy, he says, 'You'll never see the light of day.' And he says, 'I'll guarantee you before you leave here I'm gonna inject you with a, with a deadly ah . . . dose of cancer."
Clark also alleges on the tape that the government has attempted to kill other jailed freemen.
"I know of two of them, one of them at least, he was as healthy as a [expletive] horse when he went in there, and he came back . . . there was another one, I can't remember his name, they, they give him a lethal dose of 'no brains' when he come back."
Duke made the tapes during phone conversations and visits to the freemen compound in May.