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.
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
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
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
The medical effects of ricin
CNN's Sanjay Gupta explains ricin and how deadly the poison can be.
RELATED STORY: Ricin scare rattles Washington
About this Show
The Situation Room with Wolf Blitzer is the command center for breaking news, politics and extraordinary reports from around the world. Tune in weeknights from 5-7pm ET on CNN.
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