Hundreds of students in the Bay Area missed class Tuesday following threatening graffiti found in school bathrooms.
The threatening messages were found at Alameda High School in the East Bay and at Analy High School in Sebastopol, Sonoma County.
At Alameda High School, school officials reported an unusual drop in attendance after a student found a violent message scribbled on a bathroom wall Monday.
The threatening message prompted more than 200 students to skip class Tuesday, Alameda High School officials said.
"Better safe than sorry," parent Edwina Phillips said. "Sure it could be one angry kid, but all it takes is one angry kid."
The message appears to say Tuesday's date with the phrase "Everyone is dead." Snapshots of the graffiti were also posted on social media.
"I'm very concerned," parent Kathleen Davis said. "We're all on high alert and we just don't know if it really is serious."
Alameda High School's principal sent home a letter about the bathroom graffiti, saying in part "Despite our attempts, we have not been able to ascertain who created this graffiti or what their intentions were."
Parent Edwina Phillips said their first reaction was "Oh no. Here we go again. Some kid is troubled and is trying to let us know."
Meanwhile, in Sebastopol, school officials closed Analy High School after someone found threatening graffiti specific to Tuesday in a boys bathroom.
Police officers increased their presence at both schools because administrators want to "err on the side of caution."