The Associated Press

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WOODINVILLE, Wash. — Fires burned four multimillion-dollar show homes in a suburb north of Seattle Monday, and authorities found a spray-painted sign purportedly left by a radical environmental group at the scene.

The sign, a white sheet that had the initials of the Earth Liberation Front in scraggly red letters, mocked claims the luxury homes on the "Street of Dreams" were environmentally friendly, according to video images of the sign aired by KING-TV.

"Built Green? Nope black!" the sign said.

The fires started at a strip of unoccupied, furnished luxury model homes where developers show off the latest in high-end housing, interior design and landscaping. The homes are later sold.

The blazes are suspicious because they were set in multiple places in separate houses, said Chief Rick Eastman of Snohomish County District Seven. Eastman confirmed that the ELF sign was found at the scene of the fires in the community north of Woodinville, where some homes were still under construction.

The ELF, or Earth Liberation Front, is a loosely organized collection of radical environmentalists authorities say is responsible for other arsons in the Northwest.

A woman is currently trial in Tacoma for a suspected ELF fire at the University of Washington in 2001. Briana Waters, a 32-year-old violin teacher, is accused of serving as a lookout while her friends planted a devastating fire bomb.

The fire is one of the most notorious in a string of arsons that investigators say were perpetrated from the mid-1990s to 2001 by ELF.

No one was hurt in the arson at UW, but its Center for Urban Horticulture was destroyed and rebuilt at a cost of $7 million. It was targeted because the ELF activists mistakenly believed researchers there were genetically engineering trees, investigators said.