An appeals court overturned the conviction of a woman found guilty of helping with a notorious 2001 ecoterror attack that destroyed a university research center, concluding the judge made mistakes that cast doubt on the fairness of her trial.

Briana Waters, 34, was convicted of serving as a lookout during the Earth Liberation Front attack on the University of Washington's Center for Urban Horticulture in Seattle and was sentenced to six years in prison plus $6 million in restitution.

A unanimous three-judge panel of the 9th U.S. Circuit Court of Appeals ruled Wednesday that the late U.S. District Judge Franklin Burgess made several errors that raised questions about the fairness of her trial.

Waters' lawyer, Dennis Riordan, of San Francisco, said he was delighted and would move quickly to have her released pending another trial, if prosecutors decide to pursue one. Being imprisoned in Danbury, Conn., far from her young daughter, has been difficult, he said.

Waters was scheduled for release in 2013.

"We would like this to be the end of the line, but that's a question for another day," Riordan said.

The U.S. attorney's office did not immediately say whether it would retry Waters. Spokeswoman Emily Langlie said the office is reviewing the decision.

Waters was connected to a cell of radical environmentalists based in Olympia and in Eugene, Ore., who carried out attacks throughout the West from 1996-2001, causing more than $80 million in damage.

On May 21, 2001, the horticulture center was destroyed in a fire. In a coordinated attack the same morning, others in the group destroyed the Jefferson Poplar Farm, hundreds of miles away in Clatskanie, Ore.

Authorities didn't begin to solve the crimes until three years later, when one activist began cooperating. Two women later acknowledged their involvement in the university fire and testified against Waters during her 2008 trial. Rental car records suggested Waters obtained a vehicle used in the crime.

Of 13 people convicted, Waters was the only one to go to trial. She maintained her innocence and insisted that the two women lied in exchange for lesser sentences. Several witnesses testified about Waters' gentleness as a violin teacher, mother and peace advocate in Oakland, Calif.

The 9th Circuit panel took issue with several aspects of the trial.

Most notable was that jurors were allowed to review articles that purportedly were in a folder that Waters gave to an alleged coconspirator. Most of the articles were about anarchist political theory, but several advocated violence — including against well-known American institutions such as Wall Street and Disneyland.

"We believe that an appropriately skeptical eye would have excluded the articles from Waters' trial," the opinion said. "Their repugnant and self-absorbed embrace of destruction is likely to have swayed jurors' emotions, leading them to convict Waters not because of the facts before them but because she represents a threat to their own values."

Burgess, who died last spring, compounded the unfairness by not allowing jurors to see a documentary Waters made beginning in 1999 that advocated nonviolent protest, the panel held.

After jurors had started deliberating in Waters' case, a newly built mansion near Woodinville was destroyed by fire, and a sign left there proclaimed the ELF responsible. News coverage raised the possibility that the arson was tied to Waters' trial, and Burgess questioned the jury as a group to ask if anyone had been influenced by the coverage.

The panel said he should have polled jurors individually to root out any improper influence.

Seattle lawyer Mark Bartlett, who prosecuted the case as the former first assistant U.S. attorney in Seattle, said he was disappointed.

"The conviction was not only based on the evidence, but based on a fair fight in the courtroom," he said.