 At a news conference, the special agent in charge of the FBI's Pittsburgh field office, Kevin Rojack, says it appears law enforcement did not know the shooter was on the roof until he began firing. Our WTOP national security correspondent, J.J. Green, says in the coming days, the Secret Service and the law enforcement will have their hands full. There's also advanced teams that usually go ahead to check out things. I imagine they're going to check their work.