Three schools, four hospitals and a mall went on lockdown last week after someone called in threats, including threats to shoot children.
Officials said they have to take all threats seriously. Out of an abundance of caution, they locked down several locations to search for an alleged gunman.
On Monday, Covina police received a threat referencing "Citrus Medical Center," though there's no hospital by that exact name. Authorities searched surrounding hospitals, but did not find a threat.
On Tuesday, a threat was made referencing Duarte High School and Santa Anita Mall. Two days later, a threat was made at Arcadia High School. Investigators say they believe the phony threats were made by one person.
Using what they call "advanced technology," investigators identified 26-year-old Gerardo Cortez as a suspect. Cortez was arrested as he left his Monrovia home around 4 p.m. Tuesday.
"We're not going to tolerate people terrorizing children and adults in the community," said Capt. Mike Parker with the Los Angeles County Sheriff's Department.
Cortez was booked for five counts of felony making criminal threats and five counts of false report of an emergency. His bail was set at $250,000. He is due in court on Thursday.
Records show Cortez has made similar threats in the past. Last October, Cortez called in a false bomb threat at Washington Middle School in Pasadena. In addition to the middle school, he faked a threat to the Pasadena Public Health Department.
At the time, he told prosecutors he was "angry about personal problems" and pleaded no contest. Cortez was sentenced to 486 days behind bars but released after just three days and sent home on June 24.