The threat was called in over the weekend, but it kept kids out of class for about 45 minutes on Monday morning.
When school officials received the message, they searched the school and found a suspicious package. The Fresno Police Department's bomb squad was called in to check the package.
The package was determined to be non-threatening.
All students are safe and back in class.
The Fresno Police Department is still investigating the source of the voice-mail message.
