Shouts, chants, and interruptions by protestors at Brown University on Tuesday forced the cancellation of a lecture by New York City Police Commissioner Ray Kelly.

According to The Providence Journal, Kelly was drowned out by cries of “racism” and demands for “peace and justice,” and ultimately left the auditorium through a side door after university officials closed the program.

Kelly had been expected to speak about his department’s stop-and-frisk policy, which was ruled unconstitutional early this year.

In a statement, Brown University said that officials decided to close the lecture after “nearly 30 minutes of disruption by activist students and members of the local community.”

“The actions that led to the closing of this afternoon’s lecture prevented any exchange of ideas and deprived the campus and the Providence community of an opportunity to hear and discuss important social issues,” Brown University President Christina Paxson said in a statement. “The conduct of disruptive members of the audience is indefensible and an affront both to civil democratic society and to the University’s core values of dialog and the free exchange of views.”

A protestor later told the Journal that audience groups included Direct Action for Rights and Equality, Olneyville Neighborhood Association, Providence Youth Student Movement, and Fuerza Laboral. An hour before the event, several dozen students gathered and made a picket line outside the auditorium. Some carried signs reading “Ray (cist) Kelly” and “Don’t honor the police state.”

According to Brown University, Kelly’s lecture would have followed a “standard lecture format with nearly an hour set aside for direct audience questions.”