According to Tulare County sheriff's officials, the teen called the courthouse twice claiming there was a bomb inside. The building was evacuated, and authorities found no explosive devices.
Detectives tracked down the cell phone used to make the threat to a home in Pixley where they arrested a 15-year-old boy for making terrorist threats and a false report of emergency.
Deputies also arrested Gustavo Arellano Arevalo for obstructing and delaying peace officers.
The courthouse was closed for the remainder of Wednesday but will reopen Thursday morning.
Anyone with information is asked to contact the Tulare County Sheriff's Office at 1-800-808-0488.