been authenticated and verified from law enforcement directly to cnn. jeremy, thank you so much traveling with the president. on the phone right now with me a cnn law enforcement analyst and former atf executive. good both of you could be with me. let's talk about the intricacies of how this investigation moves forward. matthew, we know that atf is on the scene. you formally with your experience with atf, what will be their focus there at the church? >> well, they are going to be supporting incident command. i'm assuming fbi is leading the investigation. this is one complex crime scene with over two dozen deaths. the victims will have to remain into place. there are interviews that need to be accomplished. they need to gather around. i understand the service is