LIVERMORE (CBS SF) — Police in Livermore are keeping a close eye on Mendenhall Middle School Tuesday after a student found threatening graffiti spray painted on the back of the gym building.

A little before 8 a.m., the student alerted campus administration after noticing that the phrase “shoot all the kids at school” along with some profanity had been painted on the outside wall of the gym, said Livermore Valley Joint Unified School District Deputy Superintendent Chris Van Schaack.

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School employees contacted the police, who came out and searched the campus with a K-9 unit while a maintenance crew painted over the graffiti, Van Schaak said.

During the roughly hour-long search, the school was placed on a modified lockdown that kept kids mostly confined to classrooms and out of common areas.

Video surveillance captured the vandal’s image and police are currently searching for the identity of the suspect, who appears to have started spray painting at the campus but then left a trail of graffiti through the school’s back fields and on an adjacent Little League field, Van Schaak said.

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Officers will remain at Mendenhall throughout the rest of the week

and the Police Department will add extra patrols at school sites throughout the day, according to Livermore police, who have deemed the campus safe.

Classes are continuing as normal for the rest of the day.

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