FULLERTON, Calif. (KABC) -- Fullerton police have arrested a 14-year-old student they say was overheard threatening to shoot up a junior high school.Police say Monday morning multiple students at D. Russell Parks Junior High School told school officials they overheard a male 8th grade student say he had a gun at home and planned on shooting up the school the next day.Fullerton police searched the teen's home in Anaheim and say they found a loaded handgun and ammunition that were accessible to the youth.The 14-year-old was arrested for criminal threats and was being held at Orange County Juvenile Hall.Police praised the students who came forward after hearing the alleged threats and reminded the public to "if you see something, say something."Anyone with information about the incident was asked to contact Fullerton Police School Resource Officer Jose Paez at (714) 773-5703.Anonymous information can be provided to Orange County Crime Stoppers at 1(855) TIP-OCCS or online here.