Suspicious package that evacuated High School Library found to contain a book

The bomb squad has determined that a suspicious package discovered at the Chico High School library contained a book.
The school was placed under a lockdown at 12:36 p.m., followed by the evacuation of all students beginning at 1:50 p.m. The investigation was being centered around the school's library where staff had discovered the package.

(No, this isn't from The Onion)

Comments

But what book was it?

The Orion says the book was "Shakespeare's Four Great Tragedies: Hamlet, Othello King Lear and Macbeth,"