Portland, Oregon, -- Investigators are focusing on at least three members of the radical Earth Liberation Front as suspects in five arsons that have caused $7.4 million in damage, police say.
The five fires, from Eugene to Seattle, were linked by "signature" firebombs, they said.
While investigators are comfortable saying they are tracking a cell of the ELF, they won't identify the suspects or say where they live, The Oregonian reported Saturday.
"We think we've got the right group of people," said Eugene police Capt. Thad Buchanan, spokesman for a multi-agency task force that includes the Eugene Police Department; federal Bureau of Alcohol, Tobacco and Firearms; the FBI; Lane County Sheriff's Office; state police, and the U.S. Forest Service.
The ELF says it sabotages enterprises that harm the natural world. To date, it has claimed responsibility for attacks totaling $25 million nationwide.
A spokesman for the ELF said police were "grasping at straws" in targeting a small group of individuals.
Craig Rosebrough, who speaks for the shadowy group but insists he is not a member, said the investigators' statements show law enforcement's "pure ignorance" of the ELF.
"They seem to feel they can put a few people in jail and it'll stop the whole movement," Rosebrough said. "There's no sort of core whatsoever. It's made up of small groups that operate independently and anonymously of one another."
The first of the five fires was last Sept. 6 at a Eugene police substation. Arsonists then set fire to Glendale's Superior Lumber on Jan. 2 and the Romania Chevrolet dealership in Eugene on March 30.
On May 21, fires were set nearly simultaneously at Jefferson Poplar Farm near Clatskanie and the University of Washington's horticulture center in Seattle.
Investigators say they will rely on a fingerprint found in the ruins of the car dealership and the FBI's analyses of press releases about the fires to help prosecute the arsonists.