An anonymous, automated phone call locked down Acalanes High School in Lafayette on Monday, and within the hour officers were at a middle school a mile away chasing a second hoax — the kind of coordinated fake threat the FBI warned schools about two weeks ago.

Lafayette police found no credible danger at either campus, and by mid-afternoon Acalanes students were back in class. But the day's two incidents — a lockdown at a high school and an apparent swatting call at a neighboring intermediate school — put a Contra Costa County suburb squarely inside a documented 2026 wave of hoax emergency calls aimed at schools, one that federal investigators say is often coordinated and deliberately hard to trace.

Acalanes High School, at 1200 Pleasant Hill Road, went into lockdown just before noon Monday after what Lafayette police described as a potential threat delivered by an anonymous, automated phone call, KTVU reported (external source, opens in a new tab). The department pushed out the alert through its Nixle system as a precaution and told the public to steer clear of the campus. Officers flew drones overhead while they worked the scene, according to a separate advisory carried by SFGATE and its wire partner, Bay City News.

It ended quickly. By roughly 1:20 p.m., the department said its risk assessment had turned up no credible danger and sent students back to their usual schedule, per KTVU. Classes at Acalanes had resumed only the week before; the fall semester opened Aug. 11.

Then it happened again. Soon after the high school reopened, officers headed to nearby Stanley Intermediate School, at 3455 School Street, to sort out a report the department characterized as an apparent swatting attempt and to figure out whether anyone had actually phoned in a real danger. Both schools serve the same Lafayette community, and both drew a full police response on the first Monday of students settling into the new year.

That is why even a "no credible threat" finding, like Monday's at Acalanes, rarely means the case is truly closed.

Two hoax-style calls in one afternoon, in one town, is exactly the signature federal authorities have been flagging. On Aug. 4, the FBI's Internet Crime Complaint Center issued a public advisory (external source, opens in a new tab) warning that swatting — placing false reports of an immediate emergency to trigger a large law-enforcement response — is an ongoing threat to schools, houses of worship, hospitals and government buildings nationwide. The bureau urged schools to build response plans and to watch for tells like calls placed over internet phone services, a lone caller with no corroborating witnesses, and details that don't line up.

Investigators say the calls are frequently orchestrated. "If they're hitting 12 or 15 schools in a particular jurisdiction or a particular state all at once, that is absolutely a coordinated attack," James Turgal, a former FBI executive assistant director, told The 74 (external source, opens in a new tab). The same outlet reported that a coordinated run of hoaxes hit dozens of U.S. college campuses in the opening weeks of the previous fall term, upending classes for more than a million students.

The frustration for police is a mismatch in speed: a call engineered to empty a school takes seconds, while unmasking who placed it can take weeks. The traffic is routinely bounced through spoofing services, overseas relays or AI-generated voices. That is why even a "no credible threat" finding, like Monday's at Acalanes, rarely means the case is truly closed.

It also doesn't erase the toll on the people who lived through it. Mo Canady, executive director of the National Association of School Resource Officers, has argued that responders cannot let repetition breed complacency: "The minute you [get complacent], it's going to be the real thing, and you're going to pay the consequences for thinking that way," he told The 74.

Lafayette police had not, as of Monday evening, said whether the Acalanes and Stanley calls were connected or whether either had been referred to federal investigators. The Acalanes Union High School District did not issue a public statement beyond the department's alerts.