"This case is not about split-second decision-making," Blackwell said.

In response, attorney Eric Nelson focused the defense's opening statement on Floyd's use of fentanyl and methamphetamine and his resistance to the arresting officers.

Nelson also sought to establish doubt as to the precise cause of Floyd's death, saying it was not Chauvin's knee, but a combination of drug use and preexisting health problems. And he defended Chauvin's actions as being within proper training.

"You will learn that Derek Chauvin did exactly what he had been trained to do over the course of his 19-year career," Nelson said. "The use of force is not attractive, but it is a necessary component of policing."

On Monday morning, Floyd's family members and several attorneys knelt for 8 minutes and 46 seconds outside the courthouse to commemorate the time Chauvin was originally reported to have stayed on Floyd's head and neck.

"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," said Floyd civil attorney Benjamin Crump.

The trial is being held at a heavily fortified Hennepin County courthouse in downtown Minneapolis, surrounded by fencing and law enforcement. Due to Covid-19 precautions, plexiglass barriers have been set up inside the courtroom and witnesses and attorneys are required to wear masks when not speaking.

MMA fighter and bystander explains a 'blood choke'

After opening statements, three witnesses testified for the prosecution about Floyd's arrest.

The first witness in the case was Jena Scurry, a Minneapolis 911 dispatcher who directed officers to the Cup Foods store, the scene of Floyd's death.

Scurry walked the jury through video, not previously publicly released, shot from a police camera across the street from Cup Foods. She was able to watch live video from that feed on the day of Floyd's death and called a police sergeant to voice her concerns about the arrest.

"You can call me a snitch if you want to," she said in the recorded call. "I don't know if they had to use force or not. They got something out of the back of the squad and all of them sat on this man, so I don't know if they needed to or not."

On the stand Monday, she explained that she called because she was alarmed by what she saw during Floyd's arrest.

"My instincts were telling me that something's wrong. Something was not right. I don't know what, but something wasn't right," Scurry said she thought as she watched the video. "It was an extended period of time."

On cross-examination, Scurry noted that at one point Squad 330, either Chauvin or former officer Tou Thau, called for a faster ambulance response. She also acknowledged that the video showed the squad car shaking back and forth as officers and Floyd struggled during the arrest.

The second prosecution witness was Alisha Mariee Oyler, an employee at the Speedway gas station across the street from where Floyd died. She noticed that police were "messing with someone" and recorded seven cell phone videos of Floyd's arrest from a distance, which were played in court.

"I always see the police, they are always messing with people, and it's wrong, and it's not right," she told the court.

The third witness of the day was Donald Wynn Williams II, a professional mixed martial arts fighter who stumbled upon the scene of Floyd's arrest and was one of the most vocal bystanders.

Relying on his MMA experience, he testified that Chauvin was doing a "blood choke" on Floyd, a hold on the neck that can cut off circulation to the brain. He testified that he and Chauvin made eye contact after Williams mentioned the blood choke out loud.

"When I said it, he acknowledged it," Williams said.

His testimony will continue on Tuesday.

How two lives collided

Chauvin and another officer then arrived on the scene and struggled to get Floyd into the vehicle, the complaint states. Chauvin allegedly pulled Floyd to the ground in a prone position and placed his knee on Floyd's neck and head. His knee remained there even as Floyd pleaded, "I can't breathe," said "I'm about to die," and ultimately stopped breathing, the complaint says. He was pronounced dead at a hospital shortly after.

In his opening statement, Nelson indicated that officers perceived the vocal group of bystanders watching Floyd's death as a threat to their safety.

"They are screaming at (the officers), causing the officers to divert their attention from the care of Mr. Floyd to the threat that was growing in front of them," said Nelson.

Chauvin's defense attorney argued in opening statements that the other conditions were the real cause of Floyd's death.

"The evidence will show that Mr. Floyd died of a cardiac arrhythmia that occurred as a result of hypertension, his coronary disease, the ingestion of methamphetamine and fentanyl and the adrenaline flowing through his body, all of which acted to further compromise an already compromised heart," said Nelson.

The three charges against Chauvin are to be considered separately, so he could be convicted of all, some, or none of them.