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 . While a sophomore attending Spectrum , an alternative high school for students with behavioral issues , 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 . Soon after the September 11 attacks , " he shocked other students on his school bus by imitating an exploding plane " , reported '' The New York Times ''
September 11 attacks
September 11 attacks
Omar Mateen