Today's Situation Room:

Wolf Blitzer delivers the most important breaking news and political, international, and national security stories of the day. Tune to The Situation Room weekdays 5-7pm ET on CNN.

Wolf Blitzer delivers the most important breaking news and political, international, and national security stories of the day. Tune to The Situation Room weekdays 5-7pm ET on CNN.

April 17th, 2013
08:29 PM ET

Mapping out the marathon terror attack

CNN's Tom Foreman and former FBI assistant director Tom Fuentes discuss three critical time periods in the investigation into Monday's Boston Marathon terror attack.

RELATED: Photos of evidence

April 17th, 2013
07:01 PM ET

Gov. Patrick: No one in custody

CNN's Wolf Blitzer talks to Massachusetts Gov. Deval Patrick about the ongoing bombing investigation in Boston.

RELATED STORY: Sources: Possible suspect sought in Boston bombing

April 17th, 2013
06:57 PM ET

Obama: Gun lobby 'willfully lied'

President Obama criticized the NRA and a group of senators for blocking an expansion of background checks for gun sales.

RELATED STORY: Senate rejects expanded gun background checks


Filed under: Barack Obama • Guns
April 17th, 2013
06:46 PM ET

The medical effects of ricin

CNN's Sanjay Gupta explains ricin and how deadly the poison can be.

RELATED STORY: Ricin scare rattles Washington


Filed under: Ricin • Sanjay Gupta