SAN DIEGO (NEWS 8/CNS) - San Diego police were conducting an investigation Monday morning at Rancho Bernardo High School following the discovery of about 20 spray-painted messages on campus, with at least some of the graffiti threatening a school shooting, police said.

At least one of the messages made an apparent reference to the deadly shooting on Valentine's Day at Marjory Stoneman Douglas High School in Parkland, Florida, and threatened a shooting would happen at noon Monday on the campus at 13010 Paseo Lucido in Rancho Bernardo.

A photograph of one of the graffiti messages was posted to Facebook Monday morning and read: "2/26 12:00 school shooting 'Florida was NOTHING!!"' We blurred the reference it made to the recent school shooting in Florida.

Rancho Bernardo High threat 3
Rancho Bernardo High threat 3

Viewer submitted photo for use by KFMB

The message was written in black spray paint on the side of what appeared to be a temporary structure on campus.

School officials say after seeing these messages, many students were disturbed and opted to leave school early.

"It's disturbing for anyone to see, let alone our own staff, students and parents. I absolutely understand their reaction and desire not to be at school today," Christine Paik," Spokesperson Poway Unified School District

Police were notified of the messages around 6:30 a.m. Monday and officers were still on campus two hours later investigating the messages, Officer Billy Hernandez said. It wasn't immediately clear if there was a credible threat to the school.

Below is the initial statement that went out to parents from the school:

Dear Rancho Bernardo Families

This morning we discovered threatening messages spray painted throughout our campus. We immediately contacted San Diego Police Department who are on campus investigating. At this point, the SDPD do not believe this to be a credible threat. We will continue to have police presence on campus for the remainder of the day and throughout the week.

We also want parents to be aware that after seeing the vandalism, many students elected to leave campus before school started. We will be sending additional communication to families later today.

As always, the safety of our students and staff is paramount.

Dave LeMaster Principal RBHS

Facebook Video: Chopper 8 over Rancho Bernardo High following campus threat.