In the North Bay, a graffiti death threat sent students home early Tuesday. Sebastopol police say it was a violent message written in a bathroom at Analy High School.
The administration took the message seriously and sent the 1,100 member student body home at noon.
Wednesday, classes will resume with extra officers visible on campus.
"This is the reality of what we live in today, and we've got to take every threat seriously," Sebastopol Police Sgt. Joseph Furry told KTVU.
Police headquarters are situated only a few hundred yards from the high school, so officers arrived swiftly, when the graffiti was found at the start of the school day.
"The writing on the wall had a specific threat mentioned and a specific date mentioned and that date was Tuesday," explained Furry.
The threat was scrawled in the stall of a boy's second-floor restroom.
It was not there when janitors cleaned and secured the building Monday evening.
Police believe it was written Tuesday morning between 7 - 7:45 a.m.
They declined to specify the message, but observers said the words read, "many will die."
"That seems serious, and that's actually scary, " freshman Nick Avila-Rose said, as he waited to be picked up at school.
Avila-Rose and dozens of other students were off-campus at a field trip Tuesday, visiting colleges in San Francisco.
The absent students heard what was happening from their teacher, and from classmates who texted them.
"Some people were like, 'thank God that I wasn't there'", said Avila-Rose.
"Some people were comforting other people, and texting back asking, 'are you okay?'"
Alameda High School also discovered menacing graffiti in a school bathroom on Monday. It appears to read, "Everyone is Dead" and the date 2/27/18.
Officials at Alameda High decided to keep school open. But Analy closed at noon, and guided students who couldn't get picked-up immediately to wait in the library.
In an e-mail blast to families, administrators explained "There is no immediate threat but it is our choice to err on the side of caution."
Another e-mail later in the afternoon announced plans to re-open Wednesday, with the reassurance
"We will continue to diligently monitor the safety of our students and staff."
Students seemed to feel comfortable returning to campus.
"Well they're going to bring police officers into the school for the next few days," said freshman Colin Walker.
Analy was not evacuated because the threat was not considered imminent.
Early dismissal allowed for a thorough police search of campus.
"Right away I thought it sounds like a copycat," parent Mike Hearty told KTVU, as he picked up his sophomore son.
Hearty believes everyone in the school community is sensitive to the risk in light of the mass shooting in Parkland, Florida.
He approves of Analy's cautious approach.
"It's better to be safe in situations like this, because after all, we've got to take care of the kids."
Sebastopol is in west Sonoma County- a city of 7,000 with a small-town vibe and a low crime rate.
But police are aware, school violence can break out anywhere.
"A lot of people are upset with what's going on, and nobody thinks it's going to happen in their town," said Sgt. Furry.
"But if you look at the places it has happened, a lot of them are places that weren't on the map before."
Administrators call the scare a "stark reminder of the realities faced in today's society."
Families share that distress.
"Florida, it's terrible. Look what happened in Colorado too," said Irene Avila, picking up her grandson Nick.
"We're not safe any place any more. So what are you going to do? You have to watch your kids at home too."
Police say they have leads into the graffiti threat, and that it may be connected to previous incidents on campus.