With the key evidence turning out to be an innocuous vaccine rather than a lethal biological weapon, authorities must sort out what to do with two men who in just days went from suspected terrorists to bumbling scientists.

Federal prosecutors' decision could be revealed Monday evening at a detention hearing for Larry Wayne Harris. Harris and William Leavitt Jr. were arrested last week and charged with felony counts of possessing a biological agent for use as a weapon.Those charges now could be reduced or thrown out altogether.

Leavitt was released from jail on his own recognizance Saturday, when FBI tests found the material seized from the men was a safe anthrax vaccine rather than military-grade anthrax capable of slaughtering a city.

Harris, put on probation after a 1995 conviction for carrying another biological agent, bubonic plague bacteria, remained jailed in Las Vegas.

FBI agents continued to investigate, and on Sunday they removed box loads of materials from Leavitt's home in the farming community of Logandale, about 50 miles northeast of Las Vegas.

It was not known what was taken. FBI agents at the scene declined to comment. FBI officials said only that their investigation was ongoing.

Leavitt's attorney, Lamond Mills, called the search "a fishing expedition."

"I think they're embarrassed, and I think they're looking for anything they can find to bring charges against Bill Leavitt," Mills said.

In Maryland, meanwhile, a government lab was testing material seized from Harris' Ohio home to determine if it is a dangerous - and illegal - biological agent, federal sources said.