Person of interest identified in Brown University shooting

Tonight in Rhode Island, a major break in the search for the Brown University killer. Three senior law enforcement officials tell NBC News a person of interest has been identified in connection with the mass shooting. And in a stunning development, the officials also noting authorities are looking into a possible connection to the murder of an MIT professor.The development 5 days into an exhaustive investigation that includes combing hours of surveillance footage pulled from homes and businesses in the area ...