The man fled the scene and got away, triggering an investigation that has closed Peasley Canyon Road near West Valley Highway since Wednesday afternoon, frustrating commuters who use the busy roadway.
"It's highly unusual and very suspicious," said Dave Colglazier of the Auburn police.
The incident began at about 4 p.m. Wednesday when a uniformed federal agent driving through the area in a marked vehicle spotted smoke coming from a brushy area about 15 feet off the roadway.
The officer pulled over and walked toward the fire with an extinguisher, then spotted a man standing beside a dark SUV near the fire.
When the man saw the federal agent, he jumped in the SUV and fled the scene. The agent attempted to follow the man but he got away.
When the officer returned to the smoky fire, he made a disturbing discovery - the man had been burning flooring material, carpeting and towels that were covered with blood.
"There was a fair amount of blood on the items that appeared to be cut away from a floor, and towels that appeared to be used to clean up a mess like that," Colglazier said, adding that the man evidently had been trying to destroy the items by burning them.
He said detectives are being methodical and slow as they continue to gather evidence Thursday morning - to make sure they miss nothing.
Police now are trying to learn where the blood came from or if there is another crime scene somewhere. The Washington State Patrol is assisting in the investigation, and the bloody items will be examined at the WSP crime lab, Colglazier said.
He said it's possible that DNA found on the bloody items may help lead them to the suspect or a victim.
"It's highly unusual and very suspicious based on the material and the condition that it's in," he said, adding that the blood-stained flooring and towels were rolled up inside the carpet.
Auburn police are asking anyone who saw the dark SUV or who knows anything about the bizarre finding to call them.