The sale was made with no background check and was finalized in a parking lot.
http://www.motherjones.com/politics/2016/07/dallas-police-shooter-bought-ak-47-facebook
http://www.motherjones.com/politics/2016/07/dallas-police-shooter-bought-ak-47-facebook
In 2014, Micah Johnson, who killed five police officers and injured seven in an ambush in Dallas last week, purchased an AK-47 rifle in a deal arranged through Facebook and finalized in a Target parking lot, according to the New York Daily News. In an interview with the Daily News, the seller, 26-year-old Colton Crews, said that Johnson "didn't stand out as a nut job. He didn't stand out as a crazy person at all." In fact, because Johnson had been a US military service member, Crews said "he was like your first pick when you're selling a gun to somebody."