 Security measures for this week's Republican National Convention, because that starts today, called for unity in the wake of the shooting, urged the public not to make assumptions about the shooter's motive or his affiliations. We don't know details about any of that right now. Authorities identified the shooter as Thomas Matthew Cooks. He's a 20-year-old. They have yet to establish any kind of motive for the shooting right now. Crooks was neutralized by the Secret Service, according to the agency, meaning they killed him.