An unidentified Chicago police officer removes himself from marching protesters on Michigan Ave., during a demonstration Friday, May 18 2012, ahead of this weekends' NATO summit in Chicago. (AP ... more 
An unidentified Chicago police officer removes himself from marching protesters on Michigan Ave., during a demonstration Friday, May 18 2012, ahead of this weekends' NATO summit in Chicago. (AP Photo/Charles Rex Arbogast) less 
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Associated Press | Photo By Charles Rex Arbogast
Fri, May 18, 2012 7:19 PM EDT