Authorities believe that they have ended the mystery of who threatened to shoot an AK-47 assault rifle at schools and a hospital in the San Gabriel Valley.
Gerardo Cortez, 26, was arrested Tuesday afternoon as he was leaving his Monrovia home,
He is scheduled to appear in court Sept. 19.
At a news conference Tuesday evening, Sheriff's Department Capt. Mike Parker said Cortez had previously been "arrested and convicted for a similar offense." Parker said he had no details on that case.
Sheriff's Department online booking records show that a Gerardo Cortez with the same birth date was arrested in Pasadena on Oct. 25 and sentenced to 486 days on June 21. The records do not state whether the sentence was suspended or whether credit was given for time served in county jail.
That case involved bomb threats made to a Pasadena middle school, a post office and a local government building, according to media reports.
On Tuesday, law enforcement authorities said the first call in the latest series of threats was made Sept. 9 to the Covina Police Department. The caller said he was at "Citrus Medical Center."
"I have an AK-47 and I'm going to start shooting people right now," the caller said, according to a transcript of the call cited by Parker.
He said that although there is no Citrus Medical Center, authorities searched several hospitals in West Covina and Glendora that day "out of an abundance of caution."
Another call was made Sept. 9 to the Monrovia Police Department, during which the caller threatened to shoot an AK-47 at Santa Fe Middle School, according to authorities.
Other threats were made to the Santa Anita Mall in Arcadia as well as Duarte High School and Arcadia High School.
"We take these threats seriously," Parker said. "We are not going to tolerate people threatening children and adults."
More than 100 deputies and police officers, along with agents from the FBI office in Los Angeles, launched a joint investigation that led to Cortez's arrest.
He was being held at the Monrovia jail in lieu of $250,000 bail.