"The suspect in a Florida school shooting bought the AR-15-style rifle used in the attack legally a year ago, authorities said Thursday. Nikolas Cruz, 19, is charged with murdering 17 people at Marjory Stoneman Douglas High School, where he had been expelled for fighting, according to authorities. Cruz lawfully bought the semiautomatic rifle last February, according to Peter Forcelli, special agent in charge of the Miami office of the Bureau of Alcohol, Tobacco, Firearms and Explosives. The gun, a Smith & Wesson M&P 15 .223, was purchased at Sunrise Tactical Supply, according to the Associated Press. Federal law allows people 18 and older to legally purchase long guns, including this kind of assault weapon. With no criminal record, Cruz cleared an instant background check via the FBI criminal database."