Gardena police found several guns and a cache of ammunition at the home of a high school student who threatened campus violence in two social media posts this week, authorities said.

The investigation began Thursday when police received a call regarding a threat to Serra High School, according to the Gardena Police Department. Investigators identified a student who posted a threatening message earlier this week.

The teen posted a more specific threat Thursday, saying that violence would take place on campus. Detectives arrested the teen, who was not named, on suspicion of making criminal threats and possessing a firearm as a juvenile.