TACOMA, Wash. (AP) - A federal jury Thursday found a woman guilty of two counts of arson for being the lookout in the 2001 burning of the University of Washington's Center for Urban Horticulture by members of the radical Earth Liberation Front.

The judge declared the jury deadlocked on three other counts against Briana Waters, including the most significant count, using a destructive device during a crime of violence, which carries a mandatory minimum of 30 years in prison.

First Assistant U.S. Attorney Mark Bartlett said his office would decide within a week whether to retry her on the deadlocked counts.

For the arson convictions, Waters, 32, faces 5 to 20 years in prison. Sentencing was set for May 30. She closed her eyes, bowed her head and cried as the verdict was announced.

"Obviously we are thrilled with the verdict," Bartlett said. "It was a very long investigation, and we are very happy that Ms. Waters and all the people involved in the UW arson have been held accountable."

The fire, which destroyed the plant research center, was one of at least 17 fires set by radical activists with the Earth Liberation Front and the Animal Liberation Front from 1996 to 2001.

Waters maintained her innocence on the stand, despite the testimony of two women convicted in the fire and records suggesting she obtained a rental car used in the crime.

Her lawyer, Robert Bloom, insisted during closing arguments that the women, Lacey Phillabaum and Jennifer Kolar, lied on the witness stand to frame her and win lighter sentences.

"I am really really heartbroken here. I know this woman," he said. "I know she didn't commit this crime. We just have to proceed from here."

Bartlett argued that the women had no reason to identify Waters falsely.

The prosecutor portrayed Waters as an environmentally concerned student at The Evergreen State College in Olympia who became convinced that "direct action" was the best way to protect the Earth and change corporate behavior. In 1998, when she was a senior, The New York Times Magazine quoted her as saying she supported politically motivated arsons as long as no one got hurt.

She was a close friend of William Rodgers, a leader of the arsonist cell who committed suicide after being arrested in the UW fire.

Waters first came to the attention of investigators in early 2006, when Kolar said she had found documents at her home with Waters' name and remembered that Waters served as a lookout during the arson. In earlier FBI interviews, Kolar did not mention her - something Bloom seized on in arguing that Kolar was lying.

In all, more than a dozen people were arrested in connection with the arsons around the West. Waters was the only one who went to trial rather than plead guilty.

The university rebuilt the horticulture center at a cost of $7 million. It was targeted because the ELF activists mistakenly believed researchers there were genetically engineering poplar trees.

The radical group is suspected in a fire that scorched three model homes in a Seattle suburb earlier this week. A spray-painted sheet found at the scene of the fires bore the initials of the group, and appeared to protest claims the luxury homes were environmentally friendly.