(Minneapolis, MN)  --  The U.S. Department of Justice reportedly is conducting a criminal investigation of an alleged violent incident between former Minneapolis Police officer Derek Chauvin [[ SHO-vin ]] and a Black teenager in 2017.  Chauvin was convicted this week of killing George Floyd last May by kneeling on his neck for more than nine minutes.  ABC News reports the DOJ has body camera video showing the former cop hitting a 14-year-old boy in the head so hard, the teen needed stitches.  The teen repeatedly told officers he couldn't breathe and Chauvin, according to the DOJ report, held the boy down with his knee for 17 minutes.