The slogan matches one found on a bullet casing linked to Tyler Robinson, the alleged shooter of Charlie Kirk, discovered in the wake of the assassination.

Beneath the slogan, the flyer reads: "The only political group that celebrates when Nazis die," along with a QR code above the invitation to "join the John Brown Club".

The Independent found the QR code leads to a contact form, which reads: "We're building a community that's done with ceremonial resistance and strongly worded letters. If you want to make a real change in your community, let us now [sic] below."

Shae McInnis, one of the students who spotted the posters on campus, told Fox News his discovery was "appalling and so shocking".

"I immediately thought of Charlie Kirk's assassination ... so obviously I read this immediately as a threat, not only for me, but for everyone on this campus."

The group shares the name of the John Brown Gun Club, which is listed as a "leftist gun-rights group originally based in Kansas" by US NGO The Counter Extremism Project.

The Kansas-based club has spawned various other chapters, including The Puget Sound John Brown Club in Washington state, which reportedly "seeks to disrupt fascists and fascist organizations and events".

In 2020, Willem van Spronsen, a member of the Puget Sound John Brown Club, was killed by authorities "in a hail of bullets" while armed with a semiautomatic rifle, after setting vehicles on fire and throwing Molotov cocktails in an attack on an ICE detention center he'd described as "an abomination".

The club is named after John Brown, 1800-1859, an American abolitionist and evangelical Christian in the decades preceding the American Civil War. He gained notoriety for his fight against pro-slavery raiders in Kansas.

Following counter raids that included targeting a federal armoury in Virginia in an effort to start a slave liberation movement, Brown was captured, tried, and executed.

"Georgetown University has no tolerance for calls for violence or threats to the university," a spokesperson for the school said.

"The flyers have been removed, and the university is investigating this incident and working to ensure the safety of our community."

'Left-wing gun club' seeking to recruit members with 'Hey, fascist! Catch!' flyers