After being raised in New York for a few years, he moved with his family to Port St. His family was described as being moderate Muslims and "an all-American family".Behavior in school At a young age, Mateen displayed an interest in violence, the Associated Press and The Washington Post reported.
Before the shooting, he had been investigated for connections to terrorism by the Federal Bureau of Investigation (FBI) in 20.
During that period, he was placed on the Terrorist Screening Database, but subsequently removed.
In 1999, while Mateen was in the eighth grade, his teacher sent a letter to his father regarding an "attitude and inability to show self-control".
Mateen began his secondary education at Martin County High School in 2000, and at the age of 14 was expelled after being in a fight in math class, where he was briefly arrested without being handcuffed and charged with battery and disrupting school, though the charges were later dropped.
Following the Virginia Tech shooting in April 2007, Mateen suggested in a corrections officer training class that he would bring a gun to class. Days later on April 27, 2007, Mateen "was involuntarily dismissed" from the program and never became a certified corrections officer.
Mateen then worked for British-based security firm G4S Secure Solutions in Jupiter, Florida, from September 2007 until his death.
While a sophomore attending Spectrum, an alternative high school for those who have issues with their behavior, classmates told The Washington Post that Mateen cheered in support of the hijackers during the September 11 attacks and that he stated that Osama bin Laden was his uncle who taught him how to shoot AK-47s, all of this before knowing that bin Laden was the mastermind of the attacks.
After his outburst, Mateen's father arrived at the school to pick him up and slapped him in the face, with Mateen later being suspended for five days after the incident.
Mateen held an active concealed carry permit and an armed security guard license.
He passed a multiple choice psychological test and Dr.
In the seventh grade, Mateen was moved to a separate class with the purpose of avoiding "conflicts with other students" and suffered from poor scholarly performance due to "many instances of behavioral problems".