CASTAIC, Calif. (KABC) -- Authorities said Santa Clarita Valley International School in Castaic was placed on lockdown Thursday as deputies investigated a "possible threat." Shortly after noon, the lockdown was lifted and parents were allowed to pick up their children, according to the Santa Clarita Valley Sheriff's Station.According to sheriff's officials, a 15-year-old student was detained on charges of making criminal threats, after he was overheard by classmates saying he was going to "shoot up the school and students."A classmate who overheard the threat Wednesday notified a parent who then contacted the school Thursday morning. School administrators then realized the student wasn't in school and contacted police.The school was placed on lockdown as deputies initiated a search for the student off campus. The student was eventually located at near his home in Piru. He was transported and booked at the Santa Clarita Valley Sheriff's Station, according to deputies.Deputies said no weapons were recovered.The student has since been released to his mother and cited to appear in court.No injuries were reported at the school, located at 28060 Hasley Canyon Rd, deputies said, but panicked parents raced to the campus fearing the worst."Teachers and sheriffs surrounded the school, which means they would have been in the line of fire, and they were willing to take that fire for my kids," said parent Erin Kotecki Vest, through tears. "I can't thank them enough."