hen Donald Williams II saw the police car, he debated continuing on his way. He’d snuck out of his place on 25 May 2020 for a few minutes’ break from his family – just a quick hop to Cup Foods for an energy drink, something Williams had done countless times before. It had been a productive day of fishing on Valentine Lake with his 13-year-old son. They planned to fillet and cook the three bass they had caught for dinner; Williams didn’t want to keep his son waiting. He’d haphazardly thrown on his navy blue Northside Boxing hoodie and two mismatched socks that peaked conspicuously out of his flip-flops. He wasn’t dressed for a serious interaction. Williams made it to the convenience store door before he stopped in his tracks. “My energy stopped me,” Williams explained to a jury nine months later at Derek Chauvin’s trial for the murder of George Floyd. “The surroundings stopped me. The energy was off and I just couldn’t get in the door.” The 33-year-old Williams moved to the sidewalk hugging the convenience store to observe the situation, something he’d learned working corporate and private security for more than a decade. A police car was pulled up to the curb with an officer standing at its rear side. A Black man was on the ground, stomach down, his wrists handcuffed behind his back. A second officer had his left knee on the side of the man’s neck, pinning him to the concrete alongside the vehicle. The man struggled to raise his head, his face contorted in pain. He was in obvious distress. He was George Floyd and his murder would set off a summer of protests and racial reckoning in the United States and across the world. Williams, who had lived in southern Minneapolis all his life, joined two other bystanders at the edge of the sidewalk, now just feet away from the police car’s rear side. Williams noticed a third officer behind the car, also holding down the man’s lower half. Floyd told the officer kneeling on his neck, Derek Chauvin, that he couldn’t breathe. He asked for his mother. Chauvin didn’t respond. Williams quickly realized he had come upon a life-or-death situation. Williams identified himself to the officers as a trained fighter with the local Minnesota Mixed Martial Arts Academy. Why this would make a difference has everything to do with William’s athletic skillset. As a professional fighter who had drilled chokeholds for a decade, Williams was a crucial eyewitness at Chauvin’s trial for the murder of Floyd. Williams was able to explain to the jury how Chauvin’s knee created the same pressure to Floyd’s neck as a side choke, which cuts off blood circulation and oxygen to the brain, causing its recipient to lose consciousness. A lifelong wrestler understands weight and leverage, which is how Williams could articulate that every time Chauvin adjusted his knee on Floyd’s neck, it had the same effect as a fighter tightening a hold on their opponent. Every shift of Chauvin’s shoulders, of his planted back foot – Williams explained the correlation. Williams started wrestling at age 12 when he earned a place on the Minneapolis Edison High School team, then continued competing through college. In 2009, Williams discovered MMA at Greg Nelson’s Academy in Brooklyn Center. Williams was one year away from a dental hygienist’s degree when he decided to train full-time under Nelson, a former NCAA Division I wrestler who has produced three UFC champions. As an amateur bantamweight, Williams rattled off six consecutive wins in five months. Williams had a 6-6 record as a pro, his last bout a loss in March 2019 in which he tore a ligament in his knee. One year later, Williams found himself on the sidewalk outside Cup Foods, his studied eyes acutely aware of what he as witnessing. “I was able to focus and analyze on what was happening because of my martial arts training. It moved fast for everyone, but it was slow for me,” Williams told the Guardian last week. “All these comments [Floyd] made or someone else said, it triggered things in my brain. I knew the reason why things were happening [with Floyd].” “My head hurts,” Floyd said, according to Williams’s testimony, as Chauvin’s knee remained wedged in his neck. “My head hurts,” he repeated. “I need to get up.” “That’s a blood choke,” Williams yelled out to the officers. Blood chokes restrict the blood flow from and to the brain and cause targets to pass out. Law enforcement officers trained in these types of chokes at the Academy alongside Williams all the time. Maybe one would recognize its meaning – and danger. Chauvin looked up and he and Williams made eye contact. The officer never looked Williams’ way again. Minutes passed as Williams tried different ways to get Chauvin to release his knee. Frozen on the sidewalk, Williams called the officers “bums,” as he watched Floyd’s eyes rolling in the back of his head. About a dozen spectators had now gathered on the sidewalk. Williams noticed a young man exit the store, walk around the crowd to get a better vantage point and break down crying before being ushered back into the store. When the teenager came back out a second time, Williams talked him out of confronting the police. “This isn’t the time or place,” Williams told him, holding his arm up stop him. As Floyd faded in front of his eyes, Williams intensified his pleas to the officers. He had studied anatomy in college and understood time was running out. “Just like in MMA, you can tell when someone is getting tired or getting choked out,” Williams said at the trial. “I could see the man’s breathing becoming tremendously heavier and you could see and hear him struggling to gasp for air. “My stomach hurts,” Floyd said. It was the last thing Williams heard him say. Seconds later, Williams saw him go lifeless. As the ambulance drove away, Williams didn’t know what to do with himself. Nervous and feeling lost, he did something no one thinks they’d ever need to do. Williams called the cops on the cops, telling the operator that he’d just witnessed a murder. William’s girlfriend and kids were upset with worry when he returned home. “I left the house for what I thought would be five minutes, but I was gone for over two hours,” said Williams A shaken Williams tried to explain to his family the gravity of what he’d just been a part of, but he struggled to find the words. He retreated to the basement and waited for the story to hit the media. Williams doesn’t know how much time passed before he heard the basement door creak open. “You can come up now,” a family member called down. “We believe you.” For the next nine months, Williams waited to share what he had witnessed. He declined most interviews, limited public appearances and stopped participating in social media altogether. If he was recognized, Williams always steered conversation away from Floyd’s death – steps taken to preserve his testimony and protect himself and his family. Floyd’s death has taken a mental toll on Williams and his family. “I’m dealing with stuff, with trauma,” he told the Guardian of the effect the murder and trial has had on his life. “We all are. Everyone who watched that. We’re all dealing with it. It’s trauma.” Asked if the last year had left him fearful for his safety, Williams was blunt. “Am I fearful for my safety? Of course, I’m fearful for my safety,” he said. “I’m a Black man in America.” Williams likened the time leading up the trial to preparing for a fight – he wanted to make sure he could perform to the best of his ability as a witness in order to achieve justice for Floyd. When he took the stand in March for Chauvin’s trial, Williams had a lot of information to share – more than 20 years’ worth to be exact. There were a dozen witnesses to Floyd’s murder, but only one with a trained eye for “use of force,” the term used to describe the tactics an officer uses to subdue a suspect. Last week, Chauvin was found guilty of Floyd’s murder. Williams is expected to testify in the combined trial of the three other officers involved in Floyd’s death. That trial begins on 23 August. Williams intends to be fight-ready.