Prosecutors accused former police officer Derek Chauvin of killing a defenceless George Floyd by “grinding and crushing him until the very breath, the very life, was squeezed out of him”, at the opening on Monday of a murder trial regarded by millions as a litmus test of US police accountability. The prosecutor, Jerry Blackwell, told the jury that the death of Floyd last May, which reignited the Black Lives Matter movement and set off months of protests across America and around the world, was caused by Chauvin keeping his knee on the neck of the dying man for more than nine minutes even after he stops breathing. “What Mr Chauvin was doing, he was doing deliberately,” Blackwell said as he outlined his case to the jury in the court room in Minneapolis, the city where Floyd was killed. The prosecutor said Chauvin used excessive and unreasonable force “without regard for Floyd’s life”. Blackwell said it was “an assault” that led to the victim’s death. Chauvin, 45, has denied charges of second- and third-degree murder, and manslaughter, over the death of the 46-year-old African American man who was detained on suspicion of trying to buy cigarettes with a counterfeit $20 bill last May. The former officer, who was fired, faces up to 40 years in prison if convicted of the most serious charges. Chauvin’s lawyer, Eric Nelson, told the jury in his opening statement that the evidence will show that Floyd was under the influence of drugs and that the force used against him was reasonable because of his behaviour. Outside the fortified courthouse, the Floyd family lawyer, Benjamin Crump, declared the trial a test of American justice and said that the world is watching. “Today starts a landmark trial that will be a referendum on how far America has come in its quest for equality and justice for all,” he said. A group of protesters held signs that read “Minneapolis will never forget George Floyd” and “Mr George Floyd is not on trial, Derek Chauvin is”. Blackwell showed the jury a nine-minute-and-29-second video of Chauvin kneeling on Floyd’s neck, the footage that had shocked millions of Americans last year and prompted the huge racial justice protests that swept the US and beyond. “You can believe your eyes, that it was homicide, it was murder,” he told the jury, some of whom had not seen the video before. In the recording, Floyd can be heard saying 20 times that he could not breathe and 10 times that he was dying. He repeatedly called out for his dead mother. Blackwell said that the dying man can also he heard to say “Tell my kids I love them” and “I’ll probably die this way. I’m through, I’m through. They’re going to kill me.” Blackwell said that Floyd was no longer breathing for the last minute that Chauvin was kneeling on his neck. The prosecutor said that the officer not only failed to fulfill his legal duty to help Floyd but stopped anyone else from assisting him, including a firefighter trained in first aid. Blackwell said that even when Chauvin was told by a paramedic that Floyd no longer had a pulse, the police officer kept his knee in place. “You’ll see that he does not let up. He does not get up. Even when Mr Floyd does not even have a pulse, it continues on,” he said. He said the jury will hear testimony from a police officer who arrived on the scene while Floyd was held down who will say that at that point there was no need for the force used by Chauvin. The prosecutor also said that the Minneapolis police chief, Medaria Arradondo, who fired Chauvin shortly over Floyd’s death, will testify that the former officer’s conduct was “not consistent” with Minneapolis police department training or protocol. “He will tell you it’s excessive force,” Blackwell said. The prosecutor said that Floyd’s arrest was unnecessary in the first place as passing a counterfeit bill, even if intentional, is a misdemeanour for which the police could have written a ticket. Nelson said in his opening statement that he will show that his client’s behaviour was reasonable under the circumstances because Floyd was under the influence of drugs at the time of his arrest. He said witnesses testify that Floyd had taken opioid pills shortly before he was detained and that at times he “passed out”. “The evidence will show that when confronted by police, Mr Floyd put drugs in his mouth in order to conceal them from police,” he said. Nelson said that Floyd took a “speedball” of opioids and methamphetamine, and that as a result he was struggling violently against arrest which necessitated use of force. “Derek Chauvin did exactly what he had been trained to do over his 19-year career,” he said. The outcome of the trial may well centre on the cause of death. Nelson said medical evidence will show the presence of drugs as well as other medical issues including coronary disease and an enlarged heart were the cause of death. He said there is no medical evidence of asphyxiation. The official autopsy and an independent autopsy at the time concluded that the main cause of death was homicide. Blackwell said: “This was not a heart attack.” The first prosecution witness was a 911 dispatcher, Jena Scurry, who told a police supervisor she was concerned at seeing the officers “sat on this man” in a live feed from a street camera. Blackwell said of Scurry’s testimony that “she called the police on the police”. Later in the afternoon, prosecution witness Donald Williams, 33, told how he watched Floyd “slowly fade away” from close by, even as bystanders implored and berated the police holding him. Williams told the court that he could hear and see Floyd in distress and his martial arts experience indicated to him that Chauvin was choking out Floyd as he kneeled on his neck. The jury, and the public watching in court or around the world by livestream, was shown some devastating clips of Chauvin allegedly “shimmying” in what Williams said was a martial arts move, altering his position very slightly so that it put more pressure on – as a fighter does when they have someone in a hold. Williams heard Floyd talking about how much pain he was in, his distress as he said he couldn’t breathe, apologized to the officers and begged for his life. “The more that the knee was on his neck, and the shimmying going on, the more you see him [Floyd] slowly fade away. His eyes rolled to the back of his head,” Williams said. He described Floyd dying “like a fish in a bag”. Williams described the knee-position as a dangerous “blood choke” intended to cut Floyd’s airway. Williams has previously been heard but unseen shouting angrily at the police from the sidewalk, calling Chauvin a “bum” and accusing him of enjoying what he was doing, as Floyd suffers and begs. The trial continues.