"We have a murderer out there, frankly," said Attorney General Peter Neronha said Sunday, as law enforcement prepared to release the person of interest.

MukhammadAziz Umurzokov, 18, was a stellar scholar, quick to finish his class work, and had earned a substantial scholarship to attend Brown University.

Mr. Yang described a dramatic scene in the Brown classroom, where students had assembled for a final review in preparation for an economics exam that had been scheduled for Tuesday.