Long, described as a 29-year-old black male from Kansas City, Missouri, was killed at the scene of the shooting, CBS News reports. His birthday was Sunday.
He used the name Cosmo Setenpra online, and discussed the Dallas attack on police officers and recent police shootings of black men in social media posts.
“Violence is not THE answer (its a answer), but at what point do you stand up so that your people dont become the Native Americans…EXTINCT?,” he wrote on Twitter on July 13.
Police believe the gunman killed at the scene during the gun fight was the lone attacker and no other shooters are at large. State Police Colonel Mike Edmondson said at a press conference there is no active shooter situation ongoing, but investigators are working to determine if the gunman had any assistance from co-conspirators.