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 16th, 2013
08:33 PM ET

Source: Bombs were in pressure cookers

CNN's Joe Johns looks at the nature of the explosives used in the Boston Marathon blasts.

RELATED: FBI releases new details on Boston bombs


Filed under: Boston Marathon bombings • Joe Johns
April 16th, 2013
08:26 PM ET

Letter laced with ricin sent to Senate

A suspicious letter containing ricin, a poison, was addressed to a senator, according to sources. CNN's Dana Bash reports.

RELATED STORY: Ricin scare rattles Washington


Filed under: Capitol Hill • Dana Bash • Ricin
April 16th, 2013
07:09 PM ET

Third victim was a B.U. grad student

CNN's Wolf Blitzer reports the third victim in the Boston Marathon attack was a Boston University graduate student.

RELATED STORY: Sadness, resolve as Boston comes to grips with deadly marathon bombing

April 16th, 2013
06:17 PM ET

Bombing victim's mom: Everyone loved her

Patty Campbell says Monday's terror attack in Boston doesn't make any sense. Her daughter, Krystle, died in the bombing.

RELATED STORY: 'Boston will overcome,' mayor vows amid bombing investigation