A 911 dispatcher who handled the call that resulted in former Minneapolis police officer Derek Chauvin's deadly encounter with George Floyd last year testified Monday that her "gut instinct" told her something wasn't right. 

Jena Scurry said that she was troubled by how Floyd's arrest played out.

She said she looked at mounted TV screens between other calls that showed the police interacting with Floyd. She referenced the officer putting Floyd on the pavement 

 "I first asked if the screens were frozen," she testified. "I was told that it was not frozen."

She then called a superior sergeant to report what she saw. 

"I don't know, you can call me a snitch if you want to but we have the cameras up for [squad] 320's call, and … I don't know if they had to use force or not, but 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 you or not, but they haven't said anything to me yet," she was heard saying. 

Another witness, Alisha Oyler, worked as a cashier in a Speedway convenience store across the street from where Floyd's arrest took place. She told jurors she took seven video clips on her phone. 

She told Steve Schleicher, a special assistant attorney general, that she took the clips because the police were "messing with someone." 

Donald Williams, 33, a wrestler and mixed martial artist who said he has worked with athletes and off-duty Minneapolis police officers, came upon Floyd's arrest while walking to the Cup Foods convenience store. During his testimony, he described various chokeholds and how they are used.

He described Chauvin's position with his knee on Floyd's neck as a "blood choke." As he arrived outside the store, Williams said he noticed the police vehicles.

"I noticed there were two police squad cars there…thought something's going on, should I go back to my car or not?" Williams said on the stand. 

He said he heard Floyd in distress, saying: say "My stomach hurts I can’t breathe, my head hurts, I can’t breathe… he pleaded with them." He said he pleaded with officers to check Floyd's pulse. 

At one point, Floyd apologized. He said Officer Tou Thao said "this is what happens when you do drugs," referring to Floyd being on the ground. Williams said he disagreed. 

Earlier, as opening statements were underway, Minnesota prosecutors replayed the viral bystander video showing Chauvin pressing his knee into Floyd's neck for several minutes before his death last May.

Just before 9:40 a.m. CT Monday, prosecutor Jerry Blackwell began delivering his opening statement before both jurors on the 18th floor of the Hennepin County Courthouse and spectators tuning in worldwide via livestream. Chauvin's defense, Eric Nelson, delivered his opening statement next.

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Blackwell started by describing how Minneapolis officers take an oath to respect the sanctity of life, refrain from using excessive force and to acknowledge public trust comes with the badge. He stressed to jurors that the number to remember was 9 minutes, 29 seconds — the amount of time Chauvin had Floyd pinned to the pavement with his knee last May. The White police officer "didn’t let up, he didn’t get up" even after a handcuffed Floyd said 27 times that he couldn’t breathe and went motionless, according to Blackwell.

"You will learn that on May 25, 2020, Mr. Derek Chauvin betrayed this badge when he used excessive and unreasonable force upon the body of Mr. George Floyd," Blackwell said. "That he put his knee upon his neck and his back, grinding and crushing him until the very breath, no ladies and gentlemen, until the very life was squeezed out of him."

The timeline differs from the initial complaint filed last May by prosecutors, who said Chauvin held his knee to Floyd’s neck for 8 minutes, 46 seconds. In the following weeks, demonstrators staged "die-ins" lasting 8 minutes, 46 seconds, and 8:46 became a rallying cry in the case.

Stressing the importance of the footage, the prosecution then played viral bystander video in the courtroom. It was first recorded by a bystander outside of Cup Foods at the intersection of Chicago Ave. and E. 38th St. and posted to Facebook, quickly going viral and sparking protests and demonstrations across the country last summer.

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"I would tell you that you can believe your eyes, that it's a homicide, it's murder," Blackwell said of the video, telling the juror what they will be able to see for themselves in the video. "You'll be able to see every part of what Mr. Floyd went through from him. First crying out from his effort to move his shoulder, to get his breathing, get room to breathe. You'll be able to hear his voice get deeper and heavier, his words further apart, his respiration more shallow.

"You'll see him when he goes unconscious and you'll be able to see the uncontrollable shaking he's doing when he's not breathing anymore," he continued. "The anoxic seizures from oxygen deprivation, you'll be able to see when he's going through again, breathing the involuntary gasping of the body once the heart has stopped from oxygen deficiency. And you will hear and are well aware when there was a loss of pulse."

Onlookers repeatedly shout at the officers to get off the 46-year-old Floyd. One woman, identifying herself as a city Fire Department employee, shouts at Chauvin to check Floyd’s pulse. The prosecutor said bystander witnesses would include a Minneapolis Fire Department first responder who wanted to administer aid. He said Chauvin pointed Mace at her.

"What you learn, ladies and gentlemen, is that the use of force must be evaluated from one moment to the next moment, from moment to moment," Blackwell said. "What may be reasonable in the first minutes may not be reasonable on the second minute, the fourth minute or the ninth minute and 29 seconds that it has to be evaluated from moment to moment."

In his opening statement, Chauvin’s attorney said the evidence in this case is "far greater than nine minutes and twenty-nine seconds" that Chauvin presses his knee to Floyd’s neck.

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"That the evidence has been collected broadly and expansive. Minnesota Bureau of Criminal Apprehension employed nearly 50 case agents, analysts and technicians to investigate this case. The Federal Bureau of Investigation included at least 20 additional agents in their investigation."

Investigators interviewed nearly 200 civilian witnesses in this case and over fifty members of the Minneapolis Police Department, including the officers who responded to the scene after Floyd was brought to the hospital, Nelson said.

Around 200 Minnesota National Guard members have been activated for the duration of the trial. Authorities on Monday said they will not allow the same kind of violence and lawlessness that followed Floyd's death to occur.

"We all have an obligation to keep our community safe, and we have to do that," Minneapolis police Chief Medaria Arradondo said during a news conference.

The trial will resume Tuesday with Williams' testimony. 

The Associated Press contributed to this report.