Administrators at San Joaquin Memorial and St. Anthony's School say school is closed to students and staff on Tuesday because of the threats.
The comments are lyrics from an Eminem song and allude to shooting and killing people with an multiple weapons.
Fresno Police Chief Jerry Dyer said on Monday, just before 4 p.m., Deputy Chief Pat Farmer received information from vice principal at San Joaquin Memorial about an Instagram posting from a 15-year-old sophomore.
RAW VIDEO: Press conference on San Joaquin Memorial HS threat
Dyer said an immediate investigation launched with the gun crimes unit and detectives conducted interviews at San Joaquin Memorial. Authorities were concerned that the student felt he was bullied and was going to do something at school.
Dyer said detectives went to the boy's home, but initially no one came to the door. The detectives made contact with suspect's father, called his attorney, and gave consent for search.
During the search, police say they found an air soft gun that looked like an AK-47, a 357 Magnum revolver, 12 gauge rifle, ballistic vest, 22 caliber gun, as well as ammunition.
Investigators said it was very apparent during conversation that individual needed mental evaluation. null