One is a right-wing radical, a known associate of racist hate groups who made his living inspecting septic tanks, who was once convicted of illegally obtaining bubonic plague bacteria and later boasted about how easy it would be to kill hundreds of thousands of people by releasing it into the New York City subway, the authorities charge.

The other is a mild-mannered moderate Republican, a former bishop in his local LDS Church and one-time chairman of his town board who built a thriving business maintaining fire extinguishers and spent his spare time searching for unorthodox cures for AIDS and multiple sclerosis, lifelong friends attest.But when the FBI swept down on a suburban medical clinic here Wednesday to arrest Larry Wayne Harris and William Leavitt Jr. on charges of possessing a biological toxin - believed to be deadly anthrax - for use as a weapon, the world of anti-government militiamen may well have collided with the shadowy underground of alternative medicine in a mysterious case that has produced more questions than answers.

Harris, a one-time member of the racist Aryan Nations from Lancaster, Ohio, and Leavitt, a onetime president of the Rotary Club of nearby Logandale, Nev., remained in a federal detention center here without bail Friday, pending a hearing on Monday.

They were charged even though the materials seized from a styrofoam cooler and the trunk of the beige Mercedes-Benz they were driving were still undergoing elaborate tests at a military laboratory in Maryland.

A preliminary test did not rule out the possibility the substance was anthrax, but more sophisticated tests were needed to confirm the identity, FBI officials said.

"We don't have a lot of answers," acknowledged Walter Stowe, the assistant special agent in charge of the FBI's 100-member office here. He said virtually every agent in the state was working on the case "as rapidly as possible."

Meantime, no one could explain just what brought Harris, 46, and Leavitt, 47, both armchair microbiology buffs, together in the desert with a cardboard-covered vial that Harris told an unidentified witness held enough anthrax "to wipe out the city," according to the government's court complaint.

Associates of both men Friday painted diametrically opposed portraits, one of a maladjusted oddball, and the other a pillar of his small town.