Everyone's going to have a theory on this one. Too early for conclusions, but here are the relevant areas of analysis: 1. How was the site selected and by who? What security trade-offs were made? Some sites are very difficult to secure but chosen for better access by public, and security measures are often downplayed for perception purposes. 2. At least one witness says they saw a guy climbing on the roof with a gun, and he told local police. What communications went out from the local police? What was their ability to communicate with Secret Service? Command and control is always challenging in these events. Expect to see some communication breakdowns that could have contributed to this. 3. I hear 8 gunshots. The first 3 are at a certain cadence. Those are all likely the bad guy's. The next four are quicker. Those could be return fire from police, or more shots from the bad guy. I'm betting the final shot was the police / secret service counter-sniper. 4. From the limited video I've seen, the response from the Counter Assault Team (who are known to be legit, by the way) was very quick and professional.