The last defendant in a 2001 ecoterror arson at the University of Washington in Seattle was sentenced Friday in federal court in Tacoma to four years in prison.

With credit for time served, 36-year-old Briana Waters of Oakland, Calif., will return for 11 months.

She pleaded guilty to arson and related charges in a plea deal. A jury convicted her in 2008, but that verdict was overturned on appeal.

Three other defendants were convicted and a fourth killed himself in jail.

The fire at the UW's Center for Urban Horticulture caused $6 million in damage. Members of the Earth Liberation Front mistakenly thought a researcher was genetically altering poplar trees.

The firebombs were built at Waters' home in Olympia where she was a student at The Evergreen State College.