Sources: person of interest in Brown Univ. shooting identified

Tonight, three senior law enforcement officials tell NBC News they've detained 24year-old Benjamin Ericson in connection with the mass shooting at Brown University that killed two and wounded at least nine. The officials adding they're looking into what may be an extensive mental health history and a possible connection to the university. >> How confident are you that you have the suspect.>> Oh, I'm pretty confident. >> The culmination of a 12-hour manhunt involving more than 400 law enforcement. Today, FBI ...