Authorities were discussing pending federal criminal charges for international school threats against 17-year-old Corey Johnson a week before his fatal stabbing spree in Palm Beach Gardens, Fla.
Johnson confessed on Monday to killing 13-year-old Jovanni Sierra and stabbing Elaine Simon, 43, and her son, Dane Bancroft, 13, during a sleepover at a home in BallenIsles Country Club. Johnson was charged with first-degree murder and attempted murder, the Palm Beach Post reported.
According to police, Johnson said that his Muslim faith led him to perpetrate the violent acts.
Johnson had been known to authorities as early as his middle school years, during which he made anti-Semitic and anti-homosexual statements, and claimed that he had beliefs similar to those of the KKK. Information provided to the Palm Beach County School District Police noted that Johnson was a “white supremacist” who had “violent tendencies” and had “spoken about inappropriate places to bomb.”
In January 2017, the Palm Beach County Sheriff’s Office received information that Johnson supported ISIS and had reached out to the terrorist group online in a effort to join them. Several local law enforcement agencies and the FBI met with staff at William T. Dwyer High School in Palm Beach Gardens regarding Johnson, who was a student there at the time.
A sheriff’s detective interviewed Johnson for a mental-health assessment and found that the teen sympathized with terrorist organizations. In interviews with authorities, Johnson’s mother and grandparents said he was fascinated with dictators such as Adolf Hitler, Joseph Stalin and Kim Jong-un. They added that Johnson had “recently began discovering religion” and had been studying the Quran.
The FBI informed Jupiter police that a counter-intelligence agency in Europe had investigated Johnson’s connection to several threats made via Instagram to McAuley Catholic High School in Doncaster, England. The threats were reportedly “so severe in nature that up to 100 students were removed from the school fearing some kind of attack.” British media outlets reported that in October 2016, a threat posted on Instagram warned “we will kill every single infidel student at this school.”
In the following weeks, Johnson was monitored by law enforcement, who noted that his Facebook profile picture was an image of a swastika.
The FBI hesitated to charge Johnson because he was a juvenile and “believed a redirection approach would be the most beneficial regarding his conduct.” Instead, in March 2017, the FBI obtained consent to “mirror” Johnson’s computer activity.
Agents also interviewed Johnson, who denied any affiliation with ISIS, and instructed him “to cease all social media activities related to ISIS and any other terrorist organization” and have no further contact with the Catholic high school in England.
Johnson followed the directive only until the summer of 2017, when the FBI said he returned to his former behavior online. In February, the FBI said it had gathered all of the evidence required against Johnson and that an assistant U.S. attorney had probable cause to charge the teen.
Jupiter Police checked in with the FBI on March 5 to learn the status of the pending federal charges. The agent with whom they spoke said that the affidavits would be “coming in the next several weeks.”
A week later, Johnson was arrested for the fatal stabbing in Palm Beach Gardens.