Arson has been determined as the cause of the fire that burned down the old Angle Lake school on the evening of May 31.

By a process of eliminating accidental sources of ignition, "the hypothesis is that somebody set a fire," according to King County Fire Investigator Craig Muller

Transients had occupied the building, which was boarded up.

"People were, I guess you could say, living in another part of the building," Muller said. But there were no of cut pieces of wood, and a quantity of paper products not in the area of origin, indicating that this was not a fire set to provide heat that had grown out of control.

The school had been purchased by the Port of Seattle "for future airport operations," port spokesman Perry Cooper said.

"It's an unfortunate situation," Cooper added. "It's not the way were hoping it would be torn down."