Jay Michael Lamb believed two people at a homeless encampment in Southeast Portland were stealing from other campers, court records say.

So, on March 25, he drove up to the tent in which they were sleeping, threw a road flare at it, and drove away.

The tent became "fully engulfed" in flames, leaving one man with burns on 10 percent of his body, according to a probable cause affidavit filed in Multnomah County Circuit Court on March 31. The encampment, located near the Oregon Museum of Science and Industry, burned to the ground.

Days later, using video surveillance footage, fire investigators identified Lamb, a 33-year-old unhoused man, as the driver of the van and the person who threw the road flare into the tent, court records show.

"A review of videos revealed a minivan arrive near the camp shortly before the fire and and a lit object can be seen being thrown into the camp," the affidavit says. "The vehicle then drove off as the camp became fully engulfed. The camp was a complete loss."

Multnomah County prosecutors charged Lamb with two counts of arson: one for intentional damage to property, and another for recklessly endangering another person.

"Lamb was upset with [victims] because Lamb heard [victims] had stolen items from other transients," the affidavit says.