Shortly before the attack, van Spronsen sent a manifesto to friends. In it, he wrote “I am antifa” and referred to ICE facilities as “concentration camps.” They did not report the manifesto to police.

After his death, antifa groups issued eulogies. The group Seattle Antifascist Action described van Spronsen as a “good friend and comrade” and “a martyr.” Memorials were organized in Washington and Oregon.

I encountered van Spronsen the year prior at an antifa demonstration outside Seattle City Hall. He was part of a left-wing militia that patrolled the area while carrying guns.

One extremist who later referred to van Spronsen as a “martyr” on social media went on to carry out his own attack. On August 4, 24-year-old Connor Betts killed nine and injured dozens in a mass shooting in Dayton, Ohio. He was shot dead by responding police officers.