What are the odds this guy’s laptop that he surfed at the YMCA shows that article in his browser history?
I’ll bet he left his home and wife back in IL right after he read that article. The timeline fits. The problem for an assassin is finding a low-security high-probability venue to attack. Parking a white van in DC and living in it while waiting to shoot somebody in a motorcade was near zero odds. A baseball practice field in suburban Alexandria with a YMCA for showers and Wi-Fi was PERFECT.