http://history1900s.about.com/od/1900s/qt/mckinleykilled.htm
When President McKinley was shot by Czolgosz
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Those in line behind Czolgosz and guards in the room all jumped on Czolgosz and started to punch him. Seeing that the mob on Czolgosz might easily and quickly kill him, President McKinley whispered either, "Don't let them hurt him" or "Go easy on him, boys."