The Fresno City College math, sciences and engineering building was closed through Wednesday night after a faculty member received a threatening email.
College spokeswoman Chris Monahan Bremer said the anonymous message that arrived about 8 a.m. mentioned a package in the building.
Monahan Bremer said district police searched the building "with a fine-tooth comb."
Potentially thousands of students were affected by the closing. About 125 classes were not held, Monahan Bremer said, and each class has between 30 and 100 students.
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