Brown University said a mass shooting outside the Barus and Holley building during final exams killed two people and left at least eight critically injured as investigators reviewed surveillance footage and social media.Authorities including the FBI, ATF, Providence Police and EMS imposed a shelter-in-place, cordoned nearby streets, briefly detained and cleared a person, and said the suspect — described by witnesses as a man dressed in black — remained at large; prosecutors said a handgun was believed to have been used.Brett Smiley and John Goncalves confirmed the fatalities, Dan McKee said his office had contacted the White House, witnesses Katie Sun, Timothy O'Hara and Jib Daya described chaotic scenes, and Donald Trump posted condolences as investigators searched for a motive.