He was later identified by antifascist activists at Panic! In the Discord as Robert Sterkeson, a Mesa man who runs a website called BombIslam.com. Sterkeson claimed credit on Facebook, and vowed to post a video of the stunt on his YouTube and BitChute video channels, which are full of neo-Nazi rants aimed at Jews and Muslims.

As he left Veterans Memorial Stadium in Phoenix, he got into a verbal exchange with a black man at whom he directed a stream of racist epithets. Earlier, a Donald Trump fan had been ejected for attempting to bring in a large Trump banner.

Sterkeson has a long history of such stunts. In 2018, on the same day that an anti-Semite murdered 11 people at a Pittsburgh synagogue, Sterkeson walked into a Jewish National Fund conference in Phoenix and unfurled a Nazi banner. He also has participated in anti-Muslim rallies outside Phoenix-area mosques, including one featuring notorious Islamophobe Jon Ritzheimer, a participant in the 2016 armed standoff at the Malheur Wildlife Refuge in Oregon.

Sterkeson has described himself in social media posts as being “blackpilled,” a term to describe people who have gone from being merely “redpilled”—radicalized into believing far-right conspiracy theories—to becoming deeply nihilistic “accelerationists” whose main purpose is to help modern society destroy itself. In an earlier video posted on YouTube, he also warned that he intended to bring his “stunt activism” to events featuring Democratic candidates.

This is only the latest such incident. Men from the street-brawling hate group Proud Boys have begun appearing at Democratic campaign rallies to harass people—notably at events for Bernie Sanders in particular, at which the extremists have harassed Sanders and his supporters as “socialists” and “communists.” At one event in Denver, the Proud Boys entered the rally making the white nationalist “OK” hand signal. At a Sanders event in Tacoma, Washington, Proud Boys managed to sneak into a secure media area and wave Trump flags while wearing red MAGA hats.

Proud Boys have also been making their presence felt at Trump campaign rallies, including a recent event in Colorado. “We are aligned with Trump in that we believe in America First,” said one Proud Boy. “There’s an America First agenda. And ‘America’ means everybody that’s here in America. We’re sick of people dividing each other across lines of race and ethnicity.”