At the Battle of the Crater white Union soldiers bayoneted retreating Black Union soldiers.  The Federal Official Records and memoirs of the USCT document all of these war crimes.

"George L. Kilmer, an officer of the Fourteenth New York Heavy Artillery, went into the Crater with the first wave and reported afterward that when the USCT moved forward to charge the fort, some of White soldiers refused to follow them. Pandemonium broke out when the Black soldiers could not continue the assault and started to retreat and come back into the Crater. 'Some colored men came into the Crater and there they found a fate worse than death in the charge . . . It has been positively asserted, that White men [Union] bayoneted Blacks who fell back into the Crater.'" - "The Sable Arm."  Dudley T. Cornish, New York:  Longman, Green & Co., 1956, p 274