Investigators speculated the blaze may have been set in protest of alleged police brutality after they found fliers at the scene specifically mentioning a case in which a King County sheriff's deputy was accused of beating a 15-year-old girl inside a SeaTac holding cell. The deputy has since been fired, and Seattle police had no involvement in that case.

But late Thursday afternoon, the October 22nd Coalition to Stop Police Brutality, Repression and the Criminalization of a Generation released a written statement which said, in part, that the torching of police vehicles has "absolutely no connection with October 22nd coalition or its members, and has nothing to do with the political protest it is seeking to develop," despite the fact that the torching came on the day on which the group has held nationwide protests against police brutality for the past 14 years.

"In fact we regard such acts as harmful, because they can provide a pretext for police agencies to increase attempts to repress the mass political movement required to stop police brutality," the statement said.

Just before 5 a.m. Thursday firefighters were called to a blaze at the city lot at 714 Charles Street. Crews were able to extinguish flames quickly, but three Seattle police patrol cars and a van were damaged in the fire.

City workers spotted a suspicious man just before the fire broke out, said police spokesman Jeff Kappel. As the workers tried to contact the man, an explosion occurred near the police vehicles and the man took off running.

"(The sound) was more than a gunshot. I thought it might have been a grenade," said a witness named David, who lived nearby. "And then another big boom, and that's when I got on 911."

The witness said he ran outside in his boxers to see what was going on.

"I saw just flames 30 to 40 feet everywhere. I thought it was going to blow the whole yard up," he said.

Police only have a vague description of the man seen near the city lot when the fire broke out, and the investigation is ongoing.