Oakland, Calif. (Reuters) — Weeks after more than 100 Islamic State prisoners of war escaped from a camp in north-east Syria, U.S. military advisers says some of those escapees have been identified as combatants at an Oakland school board meeting.

“Video evidence of violence at the evening meeting at La Escuelita education center allowed us to identify at least three ISIS combatants,” said Jim Jeffrey, U.S. special envoy to Oakland and the Global Coalition to Defeat ISIS.

The violence started started around 6:30 p.m. on October 25, when agitators addressed the school board with a series of demands, stormed the barricades, and fought with police. Parents alleged the school district is operating a “school to prison pipeline” and demanded that $70 million for the Alameda County probation camp be used to fund “traditional public schools.”

“Oakland has a history of being occupied, but we still don’t know which side was occupied by ISIS this time,” Jeffrey said. “We’re investigating all possibilities, including that the Islamic State is working with the school district, the police, or the dissident parent group.”