 The investigation continues into Saturday's assassination attempt in Pennsylvania. ABC's Lana Moise has more in an ABC News discussion with Secret Service Chief Kim Cheadle. The Secret Service director sitting down with our Pierre Thomas, calling the shooting unacceptable, promising transparency in the investigation. And we want to make sure that we examine everything from start to finish. And if we need to change our practices, we will absolutely do that. So the buck stops with you?