According to the Portland Police Bureau, an officer was notified that a man had driven his pickup truck through the parade route. The officer then sought to stop the individual driving east on Northeast Weidler Street ahead of him, but Mecham continued south on Northeast MLK Jr Boulevard without stopping. The officer, who was riding a motorcycle, approached the truck and ordered Mecham to stop, but he refused.
After that, the policeman attempted to stop him once more by getting in front of the truck, but Mecham made an abrupt turn onto Northeast Wasco Street, straight in front of families waiting for the parade, with the officer stating that multiple persons were "in danger of being struck". As the rage continued, Mecham slammed through a barricade, forcing people to move quickly to avoid being hit. The dangerous pursuit was continued by the motorcycle, along with an unmarked police SUV.
Sidney Mecham eventually parked his vehicle, and was later arrested and charged with reckless endangering another person, disorderly conduct, attempting to avoid police, reckless driving, and hit-and-run in an unrelated instance. Worse, he was driving on a suspended license and didn’t have insurance, the police added.