An 18-year-old Miami man has been arrested on suspicion of making a hoax threat that shut down an Escondido high school in January 2014.
Fernando Morales was arrested on suspicion of hacking into the social media account of a student at Escondido Charter High School and sending an online threat about a planned shooting that would leave mass casualties.
The student was "quickly ruled out" as a suspect, Escondido police said.
Morales has no known connection to Escondido, police said.
The case involved the Escondido Police Department, the Miami Police Department, the FBI Cyber-Intrusion Task Force, the San Diego County district attorney's office and the U.S. attorney in Miami.
"If you threaten children and schools, you will be identified, located and arrested," said Escondido police Chief Craig Carter.