Pool via ABC NewsBy BILL HUTCHINSON, ABC News(MINNEAPOLIS) — The teenage bystander who took a viral video of Derek Chauvin with his knee on George Floyd’s neck gave tearful testimony on Tuesday in the former Minneapolis police officer’s murder trial, saying that when she looks at the horrific footage she thinks how it could have been her Black father on the ground begging for his life.To protect her identity, Hennepin County District Court Judge Peter Cahill allowed the young witness, who is now 18, to testify off-camera in the televised trial and to use only her first name, Darnella, during her stint on the witness stand.Asked by prosecutor Jerry Blackwell how her life has changed since she took the 10-minute video and uploaded it on Facebook, she struggled through tears to explain.“When I look at George Floyd, I look at my dad, I look at my brothers, I look at my cousins, my uncles because they’re all Black,” Darnella testified. “And I look at that and I look at how that could have been one of them.”She said she has spent nights agonizing over what she saw on May 25, 2020, and wishes she could have done more to save Floyd, a 46-year-old Black man she had never met.“I stayed up apologizing and apologizing to George Floyd for not doing more and not physically interacting, not saving his life,” Darnella said.She said she came upon the incident while walking her 9-year-old cousin to the Cup Foods store to by snacks, and asked her cousin to go into the store while she circled back to where police officers had the handcuffed Floyd prone on the ground next to a patrol car. She identified Chauvin in court as the officer she saw with his knee on the back of Floyd’s neck.Darnella said she immediately pulled out her cellphone and started recording video.Asked by Blackwell to describe what she saw, Darnella said, “A man terrified, scared, begging for his life.”“It wasn’t right,” she said. “He was suffering. He was in pain. I heard George Floyd saying, ‘I can’t breathe. Please get off of me.’ He cried for his mom. It seemed like he knew it was over for him.”She said that when she started recording, she was the only bystander around. Soon a crowd gathered and began yelling at the officers to get off of Floyd, she said.Asked by Blackwell if she witnessed any violence at that particular instance, she said, “Yes, from the cops.”She said that the more bystanders pleaded with Chauvin to relent, the more he seemed to use force.“If anything, he was actually kneeling harder. He was shoving his knee into his neck,” she said of Chauvin.She said at one point, Chauvin and a fellow officer, Tou Thao, put their hands on their Mace canister, apparently to prompt the crowd to back up as witnesses grew louder and shouted expletives at the officers. She said nothing the bystanders said to Chauvin seemed to matter.“He just stared at us, looked at us,” she said. “He had a cold look, heartless. He didn’t care.”She said Chauvin refused to let up even when paramedics initially arrived and attempted to check Floyd’s pulse.She said a paramedic “checked his pulse first while Chauvin’s knee still remained on George Floyd’s neck.”Under cross-examination from Chauvin’s attorney, Eric Nelson, Darnella conceded that she did not witness any part of what happened prior to her arrival, nor did she hear the conversations between the officers.Nelson asked her about all the cursing and shouting at the officers from bystanders, asking if the crowd became louder and hostile as the incident went on.“More so as he [Floyd] was becoming more unresponsive,” she said.Darnella’s 9-year-old cousin was also called to testify off-camera. She said that when she emerged from Cup Foods, she saw Chauvin with his knee on Floyd’s neck. When an ambulance arrived, she said she saw paramedics ask Chauvin to get up so they could check Floyd’s pulse.“I was sad and kind of mad cause I felt like he was stopping him from breathing,” she said of Chauvin.Mixed martial arts fighter says Chauvin used “blood choke”A professional mixed martial arts fighter who testified in graphic detail about seeing Floyd’s life being squeezed out of him by a “blood choke” returned to the witness stand on Tuesday, presenting the defense with what legal experts said was an uphill battle to discredit him.Donald Williams II — a 5-foot-6, 135 pound bantamweight who fights under the nickname “DWill II” — testified for the prosecution on the first day of the trial. He said he was headed to the Cups Foods store in Minneapolis when he was drawn to a commotion. He said he saw police officers pinning a handcuffed Black man to the ground and Chauvin, who is white, grinding his knee into the back of Floyd’s neck.Williams testified that he has been a competitive wrestler since he was in high school and turned professional mixed martial arts fighter in 2009. Given his training, he was allowed leeway by Hennepin County District Court Judge Peter Cahill to describe the hold he said he recognized Chauvin was using on Floyd.He said Chauvin was using a “blood choke,” applying pressure with his knee on the side of Floyd’s neck and cutting off the blood flowing to his head.“His breathing was getting tremendously heavy and tremendously harder for him to breathe,” Williams said of Floyd. “You actually could hear him, you could see him struggling to actually gasp for air while he was trying to breathe. He barely could move while he was trying to get air.”In his opening argument, prosecutor Blackwell played for the jury a bystander video showing Chauvin with his knee on the back of Floyd’s neck for what he said was 9 minutes and 29 seconds as two other officers helped hold Floyd down. Another, identified as Thao, kept Williams and other witnesses at bay as they pleaded with Chauvin to relent.Blackwell told the jury that Chauvin “betrayed his badge” when he dug his knee into Floyd’s neck “until the very life was squeezed out of him.”Williams said he locked eyes with Chauvin at one point during the street encounter.“He looked at me. It was the only time he looked at me when I said it was a blood choke,” Williams testified.He said Chauvin was also using what fighters call a “shimmy” to tighten his hold on Floyd.Williams added that he had gone fishing earlier that day with his son. Seeing the life drain out of Floyd reminded him of how he suffocated the fish in a plastic bag.He said he saw Floyd “slowly fade away like the fish in the bag” with his eyes rolling back in his head until he stopped begging for his life and went unconscious.During cross-examination, Nelson grilled Williams about the foul language he directed at Chauvin and Thao, asking if he and other bystanders were getting angry at the officers.Williams, who also worked in security and as a nightclub bouncer, said he was angry because the officers were not listening to him. He tried to maintain his “professionalism” and in one instance stepped off the curb to approach the officer only for Thao to place his hand on his chest and direct him back.On direct examination from prosecutor Matthew Frank, Williams said he called 911 after an unresponsive Floyd was taken away from the scene in an ambulance.Asked by Frank, who played Williams’ 911 call for the jury, why he reported what he saw to authorities, Williams replied, “Because I believed I witnessed a murder.”Copyright © 2021, ABC Audio. All rights reserved.