 with investigators who still have a pretty big presence here in Pebble Park. They want to find a motive. And as of last night, the FBI was unequivocal. They don't know the motive right now. The Republican National Convention kicks off in Milwaukee today. The director of the Secret Service said this morning she's confident of the plan to keep it secure. She said the plans are designed to be flexible and will be adopted to ensure the highest level of safety. CBS's Ed O'Keefe is there.