From Gateway Pundit:

On May 30, the 38-year-old veteran confronted a group of rioters outside one of the bars he owns in Omaha and was knocked to the ground.
“From there, he fired two warning shots and tried to get to his feet, prosecutors said. As he did, Gardner got into a fight with one man, James Scurlock, 22. The two scuffled before Gardner fired a shot that killed him,” Yahoo News reports.

The incident prompted a wave of further “protests,” particularly after Donald Kleine, the Douglas County attorney, determined that Gardner had acted in self-defense and declined to bring charges.