A riot was declared Tuesday night after a group of about 100 people descended on the Portland police union headquarters in North Portland, blocked traffic, lit fires and shot fireworks Tuesday night.
When the group got to the building, someone started a fire in a garbage can that was placed next to the PPA building, KOMO News reports.
Police said someone in the crowd then used an unknown accelerant on the wooden framing around a door of the building, then lit it on fire.
Members of Portland Fire & Rescue responded and put out the fires. One person was arrested for arson.