WALNUT CREEK (CBS SF) — Police K-9 units searched for a bomb at a Walnut Creek school Wednesday afternoon after students reported finding threatening graffiti in two of the bathrooms, the Acalanes Union High School District superintendent said.

Around 12:30 p.m. or 12:45 p.m., students notified officials at Las Lomas High School, 1460 S. Main St., of the graffiti, Superintendent John Nickerson said.

Nickerson said school leaders consulted with a police resource officer on campus and students and staff evacuated to the football field behind the school at about 1 p.m. as a precaution.

About two hours later police determined there was no bomb at the school and school leaders let students leave because it was dismissal time, Nickerson said.

Students left the school shortly after 3:05 p.m., he said. Nickerson didn’t know yet what the graffiti said.

This is the second time this month Las Lomas High students were evacuated after threatening graffiti was found on a bathroom wall.

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