MINNEAPOLIS (NewsNation Now) — Opening statements began March 29 in the trial of Derek Chauvin, a former Minneapolis police officer charged in the death of George Floyd.

The trial will be streamed online because of the COVID-19 pandemic and is expected to last weeks. Twelve jurors and two alternates have been seated for the trial. NewsNation will provide live coverage of the trial in the player above.

After prosecutors presented their case for the first 11 days of the trial, the defense began making its case Tuesday.

Ex-cop Derek Chauvin is charged with unintentional second-degree murder, third-degree murder and second-degree manslaughter in the May 25 death, following an arrest that happened on suspicion Floyd used a fake $20 bill to buy cigarettes at a convenience store. The most serious charge, the second-degree murder count, carries up to 40 years in prison. Chauvin has pleaded not guilty.

Floyd, a 46-year-old Black man, was declared dead after Chauvin, who is white, pressed his knee against his neck for about nine minutes. Bystander video footage shows Chauvin pressing his knee into a handcuffed Floyd’s neck, with Floyd repeatedly claiming that he could not breathe. Floyd’s death sparked protests and civil unrest in Minneapolis and across the U.S. over police brutality, at points turning violent.

Throughout the trial, video has played a key role in evidence and testimony. A mountain of footage — both official and amateur — has been played for the jury and during witness questioning. During the second week of trial, police officials and experts have stated that Chauvin did not follow police protocol and training.

At the earliest opportunity, during opening statements, prosecutors showed jurors the widely viewed bystander video shot by a teenager that circulated the world, after telling them that the number to remember was 9 minutes, 29 seconds — the amount of time Chauvin had pinned Floyd to the pavement.

The officer “didn’t let up” even after a handcuffed Floyd said 27 times that he couldn’t breathe and went limp, said a prosecutor during opening statements.

Prosecutors have argued that Chauvin continued to kneel on Floyd even though he was not resisting, using excessive force in violation of police training, and even when one of the onlookers identified herself as a firefighter and pleaded repeatedly to check Floyd’s pulse, according to witnesses and video.

A Minneapolis homicide investigator described Chauvin kneeling on Floyd’s neck during the May 25, 2020 arrest as “totally unnecessary” and “top-tier, deadly force.”

The defense has argued that Chauvin did what he was trained to do and that Floyd’s death was not caused by the officer’s knee, as prosecutors contend, but by Floyd’s illegal drug use, heart disease, high blood pressure and the adrenaline flowing through his body.

Chauvin’s defense have said Floyd was fighting efforts to put him in a squad car as the crowd of onlookers around Chauvin and his fellow officers grew and became increasingly hostile.

Chauvin’s attorneys have sought to also show that Chauvin and his fellow officers found themselves in an increasingly tense and distracting situation, with the growing crowd becoming more frantic, agitated and angrier over Floyd’s treatment. Onlookers repeatedly shout at the officer to get off Floyd, saying he is not moving, breathing or resisting. 

Witnesses described how Chauvin was unmoved by their pleas that Floyd was in imminent medical danger, with the teenager who shot the harrowing video of the arrest testifying that the officer gave the crowd a “cold” and “heartless” stare.

The downtown Minneapolis courthouse holding the trial has been fortified with concrete barriers, fences and barbed and razor wire. City and state leaders are determined to prevent a repeat of the riots that followed Floyd’s death, with National Guard troops already mobilized.