The Gigantic 2009 monkey-wrenching occurred shortly after the tower opponents lost another costly round in their legal battle. Seattle FBI special agent Fred Gutt, with the agency's typical taciturnity, says the strike might not even be an act of eco-sabotage. "Just because one group claimed responsibility doesn't mean that they are responsible. We're not even sure if environmental concerns are the motivation for this activity."

KRKO president and general manager Andrew Skotdal, who has kept the station on the air with a weaker signal, suggested early on that the estimated $2 million vandalism might have been done by locals. "I was furious when I heard him being interviewed on the radio," says Craven. "To suggest we might have had something to do with it was just ridiculous."

But anyone could have hung up that "Wassup?" ELF banner. ELF is an enigma; it reportedly has no command structure, no leaders, no meetings, no mailing list. Its small cells are unknown to each other -- a model that "eco-terrorist" researcher Gary Perlstein traces back to Mao Zedong's guerilla warfare in China from the 1920s to the 1940s. "An ELF cell can actually be one single person," says Perlstein, professor emeritus of criminology and criminal justice at Oregon's Portland State University. "The way ELF operates -- and I'm talking about a group that doesn't really exist as a group -- as long as they believe that someone's action is in their interest, they will claim it."

ELF's self-appointed spokesman in Washington, D.C., quickly issued a press release claiming that the group had toppled the towers but acknowledged he hadn't heard directly from anyone involved. To date, says Leslie James Pickering, an ELFer who wrote a book about the group, "The only claim of responsibility I am aware of was the note left at the scene."

The unsuccessful legal battle against the towers became a "textbook case for the necessity of direct action," says Pickering. "When writing letters and protesting for a cause hasn't proven successful -- and it most often isn't -- it does not mean that the cause is unworthy, only that KRKO is unresponsive to public interest when it conflicts with their economic interest."

The FBI considers eco-saboteurs and animal-rights extremists a serious threat. The underground radicals have been linked to more than 2,000 crimes since 1979, a sizable portion of them in the Northwest, a corner of the country that tends to draw tree-, mammal- and fish-huggers who relentlessly recycle, demand cage-free eggs, and bring an almost religious fervor to their love of nature. "You can look at it as a good thing or a bad thing, but we're probably more accepting of these types of organizations than elsewhere in the country," says Perlstein. "Here, nature comes first. Animals are put on pedestals." That sentiment resonates in Ernest Callenbach's landmark 1975 novel Ecotopia, which called for the Northwest to secede from the U.S. and form a separate country dedicated to environmentalism.

The Seattle Times reported that between 1996 and 2001, 18 people were indicted on charges of ELF-related arson and sabotage in the Western U.S. Targets included a slaughterhouse, a timber-company headquarters and several buildings at Colorado's Vail ski resort. ELF also claimed responsibility for a 2001 fire at the University of Washington's Center for Urban Horticulture that destroyed decades of research as well as structures. Three women from ELF were sentenced to prison and ordered to pay nearly $6 million in restitution in that case. One of them, Chelsea Dawn Gerlach, was also involved in the Vail arson and the toppling of an Oregon power-line tower in 1999, prosecutors said.

The Snohomish Valley area, in particular, has been a hotbed of ELF activity. In 2004, ELF took credit for burning down two homes under construction. Flammable liquids were also found at other housing developments. In 2008, arsonists destroyed three massive luxury homes and damaged a fourth on the "Street of Dreams," a high-efficiency development. They left a sign that said "Built Green? Nope black!" and signed it "ELF."

More recently, following last year's attack on the towers, someone claiming to be from ELF spray-painted graffiti addressed to the Master Builders Association and KRKO on a nearby abandoned warehouse, warning: "If you continue to risk killing children, mother earth and her creations, all your holdings are targets."

The FBI says it is "casting a wide net" in its investigation of the tower toppling. Agents have actively questioned many members of the Citizens group, including Toshenika Rosford, a flower wholesaler who owns a farm adjoining the KRKO site. "I told them to look for drag marks -- because whoever did it must have huge balls," says Rosford. "I was shocked someone had the gall to do it ... somebody really put their life on the line."

Now, 14 months after the attack, tower opponents have their hopes pinned on the Federal Communications Commission. The agency has yet to approve either a permanent operating license for KRKO or a license application for the proposed 1520 AM station. Opponents have jammed the agency with objections in an attempt to sway the process. They took heart in June when the FCC requested additional information from the owners about the new station's impacts. The FCC followed up in mid-October with a letter calling the owners' response incomplete and saying that if the additional information was not received within 30 days, the application for the new station would be dismissed.

At this point, the Citizens group has exhausted its war chest. The group still owes a sizable chunk in legal fees, and is holding ice cream socials, spaghetti dinners, wine tastings and barn sales to raise money. But members believe their fight is important, with implications beyond the local community. Rural land is being developed all over the country, they say, and many small farms struggle to retain their unique character.

In their most recent fight, they pushed an amendment to the county shoreline management program that would prevent any future AM radio towers from being built in places like the valley floodplain along the Snohomish River. On Oct. 13, the county approved the amendment.

It was a sweet moment of victory in the uphill legal battle. And as Bennett says, "We're not done yet."

This story was funded with reader donations to the High Country News Research Fund