BREAKING NEWS: Ricin letter mailed to President Obama containing threats similar to those sent to NYC Mayor Bloomberg, sources tell NBC News. Letter was intercepted by U.S. Secret Service.
BREAKING NEWS: Letters sent to NYC Mayor Michael Bloomberg preliminarily test positive for ricin; letters referenced debate on guns, NYPD says
Brian Williams interviews 6 amputee survivors of the Boston Marathon bombing. Interview airs Friday.
Boston Marathon bombing victim attends senior prom, voted prom queen
Boston Marathon bombing survivor Jeff Bauman throwing out the first pitch tonight at Fenway. (via @Boston_Police)