Lockdown at Marston Middle School lifted after police sweep tied to Clairemont High threat report

Police response prompts short-term lockdown in Clairemont-area schools

A lockdown at Marston Middle School in San Diego’s Clairemont area was lifted after officers investigated a reported threat that also led to a lockdown at nearby Clairemont High School. Police ultimately determined the reported active-shooter threat was unfounded, and both campuses resumed normal operations.

The response began late the morning of Sept. 22, 2025, when police received information described as a potential threat directed at Clairemont High School. Officers coordinated with school police and initiated a safety sweep. Because of Marston Middle School’s proximity, it was placed on lockdown as a precaution while the search was conducted.

What happened during the lockdown

During the lockdown, students and staff followed standard campus safety procedures, including securing classrooms and limiting movement while law enforcement checked facilities. Police deployed multiple units to the area, and a helicopter was visible over the neighborhood during part of the response.

Authorities provided guidance for families seeking reunification while the investigation was ongoing, directing parents and guardians to designated off-campus staging locations in the surrounding Clairemont neighborhood. After the safety sweep concluded and no credible threat was found, the lockdown was lifted and normal school activities resumed.

• Police investigated a reported threat affecting Clairemont High School.
• Marston Middle School was locked down due to its close location to the high school.
• Officers conducted a safety sweep before lifting restrictions.
• No evidence was found to substantiate an active-shooter threat during the incident.

How officials describe the decision-making

Law enforcement officials characterized the response as consistent with procedures used for any school-related threat: treat the report as potentially serious, secure campuses, and verify conditions through a methodical search. Such responses are designed to reduce risk while information is assessed, particularly when campuses are close enough that a single report could affect multiple sites.

Lockdowns in threat investigations typically remain in place until officers complete a sweep and determine whether any immediate danger exists.

What remains unknown

Authorities did not publicly release specific details about the origin or content of the threat report. In incidents of this type, investigators may continue reviewing call information and any associated digital or witness evidence to determine whether the report was a hoax, a misunderstanding, or a related safety concern. No injuries were reported, and school operations resumed after the lockdown was lifted.