Officers were sent to Manual High School, 1700 E. 28th Ave., around 3:30 p.m. said John White, a police spokesman.
In a press release, Principal Jean Kennedy said the middle school received "a targeted and anonymous threat via the StopIt App".
All other schools in the Davis Joint Unified School District will remain open, but with extra security from Davis Police.
The school district said it made a decision to close the school, "out of an abundance of caution and in light of the recent school shooting in Northern California". No student, staff or other individual should be on campus at any time tomorrow.
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The company, which now sells the Chevy Bolt EV, will expand its EV platform to "multiple brands and multiple segments", she said. General Motors announced last month that it plans to expand the number of electric vehicles in its portfolio.
The school district is working with the Davis Police Department to look into the threat. Anyone with information regarding threats against a Davis school or student are encouraged to contact the Davis police on its non-emergency line - 530-747-5400 - or call 9-1-1 for emergencies.
A female student said she had "found the threat", but after detectives interviewed witnesses and compared handwriting samples, they determined that girl had written the messages herself.
At Timber Creek High on Tuesday, someone wrote threatening messages on a mirror and stall in a girls' bathroom at the school, deputies said.
Davis schools will be on a scheduled break for Thanksgiving week, and Holmes Junior High is expected to reopen following the break, on November 27. Students will not be off the hook for the missed day, as it will be rescheduled later in the year.