SIMI VALLEY ( — A Simi Valley elementary school Monday was on heightened alert after threatening graffiti was found on campus.

Simi Valley Police Department officers responded to Justin Elementary School, located at 2245 North Justin Ave, after receiving a call about vandalism around 6:40 a.m.

After officers assessed the situation and noted the nature of the graffiti, school administrators decided to close the campus at noon.

“The police department and the school district agreed that the safest thing for us to do at this point, while the investigation was going on, was to put the students in a ‘lock-in’ situation,” Officer Stephanie Shannon said. “What that really means is that they are in their classrooms, in a controlled environment and they are only allowed to leave under escort and when their parents arrive.”

Administrators contacted parents through telephone messages as well as mass email, police said.

Detectives remained on campus to investigate the incident.

Students who were not picked up early were transported to Vista Elementary at 12:45 p.m., according to authorities.

Parents said the graffiti included swastikas and racial slurs scrawled all over the bathrooms and a statement that everyone was going to die at 2 o’clock.