NEWARK (CBS SF) — The Newark Police Department said Friday it investigated a bomb threat sent to the Newark Unified School District earlier that day in a mass email.

In a tweet sent Friday afternoon, the department said it determined the threat wasn’t credible.

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The department said it was working with the district and other agencies to identify the source of the threat.

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Officers began patrolling the district office’s campus as a precaution. No students were on campus due to the district they are attending online classes due to the COVID-19 pandemic.

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KPIX will update this story when new details become available.