 Martin, we know that the roof was in range of Secret Service snipers. They shot the gunman after he opened fire. But, I mean, this might be a basic question, but should there have been an agent on that roof? Well, not necessarily a Secret Service agent. When it comes to restricting access to buildings outside an event perimeter, that's often left to local law enforcement, according to O'Grady. And I should note here that she left the Secret Service after it came out that she'd criticized Trump on social media in 2016.