Stop AI Co-Founder Missing, Anti-AI Movement Rethinks Tactics

The anti-AI movement is having a moment nobody in it wanted. In late November 2025, Sam Kirchner, the 27-year-old co-founder of Oakland-based Stop AI, went missing after allegedly threatening to go to OpenAI's San Francisco offices and, according to callers who notified police that day, "murder people." The Wall Street Journal profiles the fallout, and The San Francisco Standard reported that OpenAI and local police locked down offices in response. Kirchner's apartment in West Oakland was found unlocked, with his laptop and phone left behind and his bicycle and camping gear gone.

The sequence inside the group is the part that matters strategically. Stop AI, which Kirchner co-founded in 2024 with 45-year-old Guido Reichstadter after both had been involved with the more restrained Pause AI, held a regular meeting on November 16. Kirchner reportedly demanded access to the group's funds to purchase a weapon and, when another organizer refused, allegedly punched him repeatedly in the head. He is said to have told that same organizer the morning after, "The nonviolence ship has sailed for me." The group expelled him, alerted police, and, as The Daily Californian reports, is now openly rethinking its approach; on X, Stop AI said both Kirchner and Reichstadter were removed from the organization in 2025 and that current leadership is "deeply committed to nonviolence."

Why this matters beyond one missing person is that this is the first widely reported radicalization incident inside the small anti-superintelligence movement, the kind of episode that civil-disobedience groups spend years trying to avoid. Frontier-lab security teams that already treat OpenAI's San Francisco footprint as a soft target now have a named case to point at when they ask for bigger physical-security budgets, and non-violent counterparts like Pause AI get a differentiation moment they did not ask for.

The honest caveat is that much of this reporting is sourced through fellow activists and police tip-lines, and Kirchner has not been charged or found. What the reporting does not give you is any federal read on whether the OpenAI threats are being treated as domestic terrorism or as a mental-health matter, or how a group that stated it adheres to nonviolent activism structured its money loosely enough that a member could try to unilaterally arm himself. Those are the questions worth watching as the coalition regroups.