SACRAMENTO (CBS13) – Extra patrols are out at Rio Americano High School after a threatening note was found in a school bathroom.

School staff and sheriff’s officials say that threat was located on Friday in a school bathroom. Scrawled on a wall, the note said that school would be shot up on Oct. 22. Another note found later said that threat had been moved up to Tuesday.

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Students, parents and staff were on edge after the message was found.

“Out of all my classes we’ve locked all the doors, and every time anybody knocks on the door somebody will get scared,” said student Chase Hendrick.

“It’s just kind of disconcerting anytime they talk about a potential shooting at your child’s school,” said parent Peggy Marshall.

Parents were notified on Friday, but learned of the specifics on Tuesday.

“I mean when you look at past history with Columbine, etc., like that, you take these things very seriously,” said parent Ray Dizon.

Sacramento County Sheriff’s deputies say they are working to figure out who wrote the threat.

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“We have extra law enforcement officials on campus, we have extra adults here on campus, we’ve asked all of our staff to be a little more visible,” said San Juan Unified School District spokesman Trent Allen.

With the threat originally set for Wednesday, parents now have to decide what to do next.

“I don’t know how I’m going to feel tomorrow though, because who knows what’s going to happen tomorrow,” Marshall said.

Authorities are taking the situation seriously, although the threat has been deemed low credibility.

“[If] they see anything suspicious, any suspicious bags, people on campus, around campus, parked in cars nearby, report it right away so we can jump on it,” said Sacramento County Sheriff’s spokesperson Lisa Bowman.

The FBI and Homeland Security are involved in the investigation.

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It’s unclear if the threat is related to a student protest last week where some students felt an administrator had censored a classmate’s writing.