Santa Rosa police are investigating a threat of violence scribbled onto the wall of a girls’ restroom Wednesday at Santa Rosa High School.

Santa Rosa High School Principal Brad Coscarelli emailed parents about the incident Wednesday afternoon but said there was “no evidence to substantiate the threat” and the school would be open Thursday.

“We always take any threat to the safety of our students and staff seriously,” Coscarelli said in the statement. “Santa Rosa High will have additional support on campus (Thursday), including police officers, counselors and district office staff.”

The threat, written in black marker of a tile wall in a girls’ restroom in DeSoto Hall read “3/1 the school is gonna be shot up...,” according to a photograph of the graffiti provided by a parent who declined to be named.

Authorities said they understood the graffiti as a threat of violence for today, March 1.

But police suspect the incident may be a copycat case of threatening graffiti, following recent Bay Area incidents that included a threat discovered Tuesday at Sebastopol’s Analy High School. A 16-year-old Analy student was arrested in that case Wednesday. He was identified by his handwriting, authorities said.

Police interviewed students at Santa Rosa High School Wednesday after the threat was first reported to staff around 11:45 a.m., Lt. John Snetsinger said. Police are also looking for leads on social media.

“We’re calling it a graffiti investigation,” said Snetsinger. “But we’re putting a lot more work into it than that.”

Steve Mizera, assistant superintendent of student and family services, said the district takes these threats seriously. However, he said it decided not to release students early because the message wasn’t deemed credible.

Santa Rosa police have “a plan in place to make sure there’s more eyes” on the high school campus Thursday, Snetsinger said. He would not elaborate on that plan or say whether it involved additional uniformed or plainclothes officers.

You can reach Staff Writer Nick Rahaim at 707-521-5203 or On Twitter @nrahaim.