According to the Rancho Cucamonga Police Department, school officials alerted authorities of threatening tweets to students and staff Thursday night.
Upon investigation, police said the threats, which authorities described as "non specific," were not credible.
Police said investigators were working with the school's principal to determine the origin of the tweets.
Authorities said school will not be canceled due the incident. Although the threats were deemed not credible, there will still be an increased police presence on campus.