Derek Chauvin Under Investigation for Allegedly Brutalizing Black Teen

Derek Chauvin faces 40 years behind bars for murdering George Floyd, but that may be just the beginning, because there's another incident that is eerily similar to the killing of Floyd.

Authorities have received video of Chauvin allegedly brutalizing a 14-year-old Black teen, and the feds are now on the case.

The incident occurred in 2017, and the video allegedly shows Chauvin violently subduing the teen ... viciously striking him in the head with such force he needed stitches to close the wound. Chauvin allegedly held him down on the ground with his knee for 17 minutes as he gasped for air ... oblivious to the teen's cry that he couldn't breathe.

One of the prosecutors said there's another similarity with the 2 cases ... "Those videos show a far more violent and forceful treatment of this child than Chauvin describes in his [police] report."

The incident is now under criminal investigation. Federal prosecutors reportedly have convened a grand jury to review the case.

The incident did not escape state prosecutors, who tried to introduce evidence of the incident in the trial that just ended to show a pattern of brutality. The judge turned thumbs down on that request.

As for specifics in the 2017 incident, a woman had called police for help after she said she was attacked by her 14-year-old son and daughter.  When Chauvin arrived, he ordered the boy to get on the ground, and when he refused Chauvin allegedly hit him with a flashlight as he grabbed his throat. The now-former cop allegedly used a neck restraint that he held for so long the teen lost consciousness. The prosecutor who reviewed the video says 8 minutes in Chauvin changed positions and put his knee on the teen's back for another 9 minutes.