Two 15-year-old girls have been arrested for allegedly planning a mass shooting at Corona High School in Riverside County, California. Authorities reported that the girls had spent months devising their plan, which came to light following a tip-off from the FBI. The Riverside County school district has released additional details following the arrests, stressing the seriousness of the situation as law enforcement continues to investigate the threats. The suspects are facing charges related to this significant security concern at the local high school.