WITH HIS SHAVED HEAD, pale skin and skeletal features, Craig Rosebraugh has become the local face of environmental activism--the outspoken press aide for underground militants who are raiding animal research labs, monkey-wrenching logging equipment and torching ski resorts. For the past three years, Rosebraugh has served as the "above ground" mouthpiece Earth Liberation Front, notifying reporters across the country about their attacks.

Now, federal prosecutors are trying to find out how Rosebraugh knows about the acts of eco-terrorism. They see him as a dangling thread they can tug and unravel; pulling apart a far-reaching network of radical environmentalists. But, so far, Rosebraugh has remained tight-lipped.

Since 1997, the local U.S. Attorney has been playing cat-and-mouse with Rosebraugh, repeatedly calling him before federal grand juries and questioning him about his contacts with environmental groups. In February, the FBI raided his house, hauling away a truckload of computers, note books and personal items--evidence, they said.

More recently, federal prosecutors offered him a grant of immunity to answer their questions. If he doesn't talk, the same prosecutors have vowed to jail him.

"Whatever I say will be used against me, regardless of what they promise," Rosebraugh insists. "Or it will be used to get someone else in trouble, and that's not going to happen."

In a larger context, Rosebraugh is part of what activists fear is a national trend: Federal prosecutors are using the grand jury process to pry into the environmental underground.

Last year, Chris Vellucch, a former Sacramento Bee reporter, issued a report stating that since 1990 six environmental activists have been jailed without trial for refusing to answer grand jury questions. One activist served 158 days without being charged for any crime.

"You have no rights in a grand jury," says Vellucch, pointing out that witnesses cannot bring lawyers into grand jury rooms. "I don't care if a person's a Mafia kingpin, they are still entitled to these rights."

University of Oregon law professor Wayne Westling agrees that some grand jury reforms are necessary. "Can they be abused? Can they be used for political purposes?" he asks. "You bet."

"It is designed to be a buffer between the power of the state and the individual," continues Westling.

Grand juries are meant to ensure no one can be indicted for a serious federal crime without a panel of citizens reviewing pending evidence. But, Westling notes, there are far more investigations than in the past.

"The process isn't hampered by rules of evidence-gathering and that raises serious questions about how reliable the evidence is," says Westling.

Rosebraugh and his supporters recently got a boost when the National Association of Criminal Defense Attorneys (NACDA) released a report charging over-zealous prosecutors with violating the rights of citizens. "In the federal grand jury, the prosecutor exercises this enormous power unrestrained by law or judicial supervision," the report read.

The NACDA called on Congress to adopt reforms, including allowing witnesses to have their lawyers present when questioned by grand juries.

But reform won't come in time to help Rosebraugh. He expects to be jailed the next time he gets subpoenaed, which could be early July. "The next time I walk into the courthouse, there's a 95 percent chance I won't be coming out," he predicts.