New York City Police Commissioner Ray Kelly's lecture Tuesday at Brown University was halted after audience members disrupted the talk in protest of NYC's controversial "stop and frisk" policy.

Kelly was invited to the Ivy League institution to give a speech titled “Proactive Policing in America’s Biggest City.” It was to cover "his eleven-year tenure as the head of the NYPD, and the strategies that have enabled the New York City Police Department to drive crime down by more than 30% since 2001 while defending New York from another terrorist attack." Those strategies include "stop and frisk," the department's practice of stopping and questioning hundreds of thousands of mostly black and Hispanic men each year.