Wolf Blitzer delivers the most important news and political stories of the day. Tune to The Situation Room weekdays 5-6:30pm ET on CNN.
It's one week after Aaron Alexis opened fire at the Navy Yard in Washington, DC, and we are finally getting some answers to the question, "Why?" At a press conference today, the FBI released chilling new video of Alexis and discussed what may have led to his attack– the voices he heard, the markings on his weapons, and the electromagnetic waves that he claims were controlling him.
CNN's Joe Johns reports on the "delusional" man and tries to piece together a motive.
Outgoing FBI Director Robert Mueller talks to Joe Johns about the NSA surveillance program, Edward Snowden's leaks, and U.S. security after Sept. 11.
Rep. Jason Chaffetz discusses his call for the FBI to get more aggressive on the Benghazi investigation
CNN's Phil Black talks exclusively to the father of a man who knew the Boston bombing suspect and was killed by the FBI.
RELATED STORY: Father: 'Unarmed' son 'not crazy' enough to attack FBI agent who killed him
The FBI released photos and video of two suspects in the Boston Marathon terror attack and are asking the public for help identifying them.
If you have any tips for the FBI, call 1-800-CALL-FBI or go to bostonmarathontips.fbi.gov.
RELATED STORY: FBI releases photos, video of Boston bomb suspects
SEE ALSO: Photos: Boston bombing suspects
CNN's Chris Lawrence takes a look at how investigators are piecing together clues in the Boston Marathon bombings.
RELATED STORY: Healing in Boston as investigators seek 2 seen near bombing