Tense moments for students at East High School Friday, after the school was placed on lockdown.
Now, the FBI is investigating.
It happened around 10:30 Friday morning. Authorities, along with Hazmat crews, showed up to the school after a suspicious package was found inside a classroom.
Officials say a white powder was found inside an envelope with a letter.
The school was then placed on lockdown.
"In general, it said that this is a dangerous substance that could cause harm to your health and that the person who wrote the note indicates some malicious intent as if they did this in order to harm that person," said Mike Collier, Kern High School District Chief of Police.
Several streets in the area were closed as Hazmat crews assessed the situation.
The FBI concluded the powder substance was not harmful.