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The ex-Minneapolis police officers who were with Derek Chauvin when he killed George Floyd began testifying today in their own defense in their federal trial. That trial is now in its fourth week. The three men are accused of violating Floyd's civil rights in the second criminal case related to the murder. Matt Sepic of Minnesota Public Radio reports.

MATT SEPIC, BYLINE: The criminal charges against J. Alexander Kueng, Thomas Lane and Tou Thao aren't about what they did but what they allegedly failed to do over the nine minutes and 29 seconds that former officer Derek Chauvin kneeled on George Floyd's neck. Chauvin is serving a 22-1/2-year sentence following his state murder trial last spring. He later pleaded guilty in the federal case. His three former colleagues are accused of neglecting to get Floyd medical care. Kueng and Thao each face an additional count of failing to stop Chauvin. Prosecutors called many of the same witnesses who testified at the earlier trial. Among them was Darnella Frazier, the teenager whose viral video sparked global outrage. Audio and video recording is not allowed in federal courtrooms, but Frazier's testimony yesterday echoed the account she gave 11 months ago.

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DARNELLA FRAZIER: I heard George Floyd saying, I can't breathe. Please get off of me. I can't breathe.

SEPIC: Use-of-force experts and high-ranking Minneapolis police officers also testified for the government. They said that Kueng, Lane and Thao violated a department policy that requires officers to intervene if another is using excessive force. The witnesses bolstered another key prosecution argument that the men neglected their training. But this morning Thao's attorney Robert Paule pushed back, showing jurors photos from the police academy depicting officers using their knees to pin people to the ground. Thao testified that during his training, he routinely used his knees to restrain people. Former police officer Caree Harper is now a civil rights attorney in Southern California. She's not involved in this case. Harper says she's skeptical that the defense's focus on training might be convincing to jurors.

CAREE HARPER: There is no amount of training that is going to teach a person to be a human being. If you don't recognize you're killing someone, you should not be in the uniform.

SEPIC: Harper notes that Frazier and the other eyewitnesses, most of whom had no medical or police training, knew George Floyd was in distress. Defense attorneys are also arguing that two of the defendants, Kueng and Lane, were rookies in their first week on the job and had to defer to Chauvin, who was their training officer. Lane can be heard on body camera video twice asking Chauvin if they should reposition Floyd on his side, but the senior officer rebuffs him. Kenyen Brown, a former U.S. attorney for the Southern District of Alabama, says this just-following-orders argument could also be a tough sell.

KENYEN BROWN: I don't think it's reasonable for an officer that observes another officer engaging in unconstitutional acts to say, hey; I'm a rookie. He has an independent obligation to act, to intervene, to render medical aid.

SEPIC: Brown says the biggest hurdle for the defense is the sheer length of time that Chauvin pinned Floyd to the ground. Brown says Kueng, Lane and Thao had minutes, not seconds, to determine that Chauvin's actions were wrong and to stop him from killing George Floyd. For NPR News, I'm Matt Sepic in Minneapolis. Transcript provided by NPR, Copyright NPR.

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