The school said in the tweet shortly after 7 a.m. that the lockdown was requested by the Riverside County Sheriff's Department.
It added that parents and guardians should "wait for further instructions to bring you student(s) to school."
NHS is on Lockdown due to a possible threat requested by the Riverside Sheriff's Dept. Please wait for further instructions to bring your student(s) to school. Thank you for your patience and understanding. We will reopen the school as soon as the Sheriff's Dept deems it safe. pic.twitter.com/0Yck3lJVeO— Norco High School (@NorcoHighSchool) September 17, 2018
Within minutes, the school said the campus was cleared of any threats and students were welcome to go to school.
We are ALL CLEAR! We look forward to seeing your students! pic.twitter.com/LXfSfJfLRW— Norco High School (@NorcoHighSchool) September 17, 2018
According to the sheriff's department, Norco police received a report of a suspicious person near campus, and the school was placed on lockdown as a precaution. After a search of the campus and surrounding area, no threat or person was located.