JUPITER — A week before Corey Johnson confessed to stabbing three people — one of them fatally — in a Palm Beach Gardens home, authorities were discussing pending federal criminal charges against the 17-year-old, according to a Jupiter police report.
Johnson was arrested Monday on charges of first-degree murder and attempted murder after investigators say he killed 13-year-old Jovanni Sierra and stabbed Elaine Simon, 43, and her son 13-year-old, Dane Bancroft, during a sleepover at a home in BallenIsles County Club.
Johnson told police his faith is what led him to the violent acts.
But before the Palm Beach Gardens attack, even as early as middle school, Johnson had been on the radar of law enforcement, the report said.
In January 2017, several local law-enforcement agencies and the FBI came together with the staff at William T. Dwyer High School in Palm Beach Gardens, where he was a student at the time. The Palm Beach County Sheriff’s Office received information that Johnson supported the terrorist organization ISIS and had reached out to the group online, expressing his desire to join them.
A sheriff’s detective interviewed Johnson for a mental-health assessment and said the teen sympathized with terrorist organizations, the report said.
Investigators also learned there were several guns inside of Johnson’s residence, according to the report. His family later told investigators there were guns in his mother’s home but were locked in a safe.
When Johnson’s mother and grandparents were interviewed by law enforcement, they said Johnson was fascinated with dictators such as Adolf Hitler, Joseph Stalin and Kim Jong-un. They said he had “recently began discovering religion” and had been studying the Quran.
After the meeting, the FBI told Jupiter police that a counter-intelligence agency in Europe investigated Johnson’s connection to several threats made on Instagram to McAuley Catholic High School in Doncaster, England. Though the report does not say what the threats were, authorities said they “were so severe in nature that up to 100 students were removed from the school fearing some kind of attack.” British news outlets reported that in October 2016, a threat posted on Instagram stated “we will kill every single infidel student at this school.”
In the weeks following, law enforcement monitored Johnson’s movements and his social-media accounts, and interviewed his family. Authorities noted his Facebook account had the image of a swastika as its profile picture.
Initially, the FBI did not want to charge Johnson because he was a juvenile and “believed a redirection approach would be the most beneficial regarding his conduct.” So in March 2017, the FBI got consent to “mirror” Johnson’s computer activity.
Additionally, they spoke with the teen —who denied any affiliation with ISIS — and told 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, the report said.
By the summer of 2017, the FBI said Johnson was back to making more online posts and that they were working to bring official charges against him, according to the police report.
In February, the FBI said it had all the evidence it needed and that an assistant U.S. attorney had probable cause to charge Johnson.
On March 5, Jupiter police checked in with the FBI to see where they were with the federal charges and the agent said the affidavits would be “coming in the next several weeks.”
A week later, Johnson was in jail for the fatal stabbing in Palm Beach Gardens.