The fallout over the disturbing video of the shooting — and that it took 13 months for its release and the officer to be charged — has galvanized Chicago and created the most severe crisis for Mayor Rahm Emanuel in his time in office. Weeks of protests have followed, with demands that Emanuel and Alvarez, in the midst of a tough re-election fight, step down. The mayor forced out police Superintendent Garry McCarthy and the head of the police oversight agency, and the U.S. Justice Department opened a wide-ranging investigation of Police Department practices.