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.

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

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.

KPIX will update this story when new details become available.