IT'S NOT MINE BUT I'M NOT GOING TO LET IT BURN. >> Reporter: DANA GRIFFIN, NBC NEWS, CALIFORNIA. >>> IN MEMPHIS OPENING STATEMENTS IN THE FEDERAL TRIAL OF THREE FORMER POLICE OFFICERS CHARGED IN THE DEATH OF 29-YEAR-OLD TYRE NICHOLS LAST YEAR. PRISCILLA THOMPSON IS AT THE COURTHOUSE. PRISCILLA, WHAT HAPPENED THERE TODAY? >> Reporter: LESTE THE THREE OFFICERS HAVE ALL PLEADED NOT GUILTY TO USING EXCESSIVE FORCE, FAILURE TO INTERVENE, WITNESS TAMPERING AND MORE. FEDERAL PROSECUTORS TODAY ARGUED THESE OFFICERS TOOK TURNS BEATING TYRE NICHOLS BUT THE DEFENSE SAID THE COPS' ACTIONS WERE IN LINE WITH THEIR TRAINING. NOW, TWO OTHER EX-OFFICERS HAVE PLEADED GUILTY AND WILL TESTIFY, PROSECUTORS SA