San Diego mosque shooting suspect was previously flagged by FBI

Myles Miller, Bloomberg News on May 21, 2026

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One of the teenagers accused of carrying out a deadly shooting at a California mosque was flagged by the FBI as a potential threat last year, according to a person familiar with the matter.

Caleb Vazquez was the subject of a 2025 FBI eGuardian alert. Authorities say Vazquez, 18, and Cain Clark, 17, on Monday killed three men, including a security guard, outside the Islamic Center of San Diego before dying from what police said were self-inflicted gunshot wounds.

The FBI had no immediate comment. The eGuardian system is a platform used by federal, state and local law enforcement agencies to share and track potential threats and suspicious activity. Alerts are reviewed by a joint terrorism task force.

Authorities recovered at least 30 firearms, ammunition and a crossbow from two residences tied to the suspects and is investigating whether they had broader plans, the FBI has said.

Authorities said the pair had been radicalized online, where they met and shared White supremacist views.