Expert Witness Says Chauvin’s ‘Force Was Excessive’ 1

April 6, 2021, 5:49 p.m. ET

April 6, 2021, 5:49 p.m. ET

Los Angeles Police Sgt. Jody Stiger is sworn in before testifying today.
Still image, via Court TV

Witnesses called by the prosecution in the Derek Chauvin trial provided a deeper look at police policies on the use of force on Tuesday and gave the former Minneapolis police officer’s defense team some potential openings.

Mr. Chauvin’s defense, led by attorney Eric J. Nelson, tried to bolster its argument that the crowd that formed on the sidewalk during George Floyd’s arrest might have made it more difficult for Mr. Chauvin to render medical aid or to move his knee, which he held on Mr. Floyd for more than nine minutes.

While the first week of the trial brought emotional testimony from bystanders, Tuesday’s proceedings seemed to cement the trial into the second phase: focusing on whether Mr. Chauvin, who is accused of murder in Mr. Floyd’s death, violated police policy, or whether his actions lined up with his training. Here are the highlights from Tuesday.

  • Mr. Nelson found some testimony from prosecution witnesses that could support his arguments. Officer Nicole Mackenzie, the medical support coordinator for the Minneapolis Police Department, agreed with Mr. Nelson’s assertion that a crowd of vocal bystanders can make it difficult for an officer to render medical aid during an arrest. Lt. Johnny Mercil, a veteran of the Minneapolis Police Department and use-of-force instructor, also said that hostile bystanders could raise alarm with officers. Mr. Nelson has suggested throughout the trial that the crowd outside the Cup Foods convenience store, which yelled at Mr. Chauvin as he knelt on Mr. Floyd for nine and a half minutes, might have hindered the former officer from helping Mr. Floyd once he became unresponsive.

  • Mr. Nelson hit on a similar theme during the questioning of Sgt. Ker Yang, a crisis intervention coordinator with the Minneapolis Police Department. He asked whether an officer can “look bad” even when applying force that is lawful, and asked whether officers are tasked with weighing possible threats, such as a crowd of bystanders, when applying force. “You’re taking in a lot of information and processing it all kind of simultaneously through this critical decision-making model,” Mr. Nelson said. Sergeant Yang agreed.

  • Los Angeles Police Sgt. Jody Stiger, a use-of-force expert, told prosecutors that Mr. Floyd kicked at officers as a possible attempt to break free from their grasp. Still, Sergeant Stiger said that kick was the only such attempt by Mr. Floyd. He also said that, based on his review of body camera footage, Mr. Floyd seemed to comply with officers shortly after they placed him facedown on the pavement, with his hands cuffed behind his back.

  • When reviewing a picture of Mr. Chauvin pinning George Floyd to the ground, Lieutenant Mercil told prosecutors that Mr. Chauvin’s position was not consistent with the Minneapolis Police Department’s training on use of force. In addition, Lieutenant Mercil said that officers are trained to “use the lowest level of force possible” when controlling a subject. Mr. Chauvin kept Mr. Floyd pinned for several minutes even after he became unresponsive. Still, Mr. Nelson made some potential headway with the testimony of Lieutenant Mercil. Asked about neck restraints, Lieutenant Mercil said it generally takes less than 10 seconds for a person to become unconscious because of a neck restraint. The question could allow Mr. Nelson to argue that Mr. Chauvin’s knee did not qualify as a neck restraint, because it took several minutes for Mr. Floyd to lose consciousness.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 2

April 6, 2021, 5:28 p.m. ET

April 6, 2021, 5:28 p.m. ET

On Day 7 of the trial of Derek Chauvin, the former police officer accused of murder in the death of George Floyd, people gathered outside the courthouse and in front of Cup Foods.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 8

April 6, 2021, 4:57 p.m. ET

April 6, 2021, 4:57 p.m. ET

A patron of a laundromat near Cup Foods watching the Derek Chauvin trial on Monday.
Joshua Rashaad McFadden for The New York Times

Viewer interest in television coverage of the trial of Derek Chauvin has been high, according to ratings data from Nielsen.

Several cable channels, including CNN and MSNBC, have broadcast large portions of the trial live, and one cable network, HLN, has shown it in its entirety since the proceedings started on March 29. For several days last week, CNN’s highest ratings came in the afternoon, during witness testimony, rather than during its prime-time hours.

Mr. Chauvin, the former Minneapolis police officer accused of killing George Floyd last year, faces charges of manslaughter, second-degree murder and third-degree murder.

On Thursday, roughly 3.7 million viewers were watching trial coverage on the three channels during the afternoon testimony of former Sgt. David Pleoger, who supervised Mr. Chauvin and testified that he should have “ended” his restraint after Mr. Floyd became unresponsive. That audience was larger than the number of people tuning into any other cable program that day. “The Rachel Maddow Show,” the most watched cable show on Thursday, drew three million viewers.

On Monday, the trial continued to attract a large viewing audience. CNN’s 3 p.m. hour, which featured testimony from Medaria Arradondo, the Minneapolis police chief, averaged 1.4 million viewers, the network’s highest total for the day, including its prime-time hours. HLN had an average of 470,000 viewers between 3 and 4 p.m. on Monday, also its most-viewed hour of the day.

The Nielsen figures do not reflect people who watched the trial on separate streaming outlets or on digital devices. Court TV is also broadcasting and streaming live trial coverage in its entirety. Fox News, the most-watched cable news network, has not been carrying the trial live.

HLN, a channel formerly known as CNN2 and CNN Headline News that is owned by CNN’s parent company, AT&T’s WarnerMedia, had its highest daytime ratings since 2013, when it covered the trial of George Zimmerman, a neighborhood watch volunteer who fatally shot Trayvon Martin, an unarmed Black teenager, according to Nielsen. HLN’s audience figures only continued to spike as the week went on.

“The numbers show that there is a high level of interest,” said Ken Jautz, an executive vice president of CNN, who oversees HLN, in an interview.

“This trial raises so many prominent and searing societal issues,” he continued. “Issues of policing practices, and how law enforcement treats people of color.”

On MSNBC, viewership figures for the morning portion of the trial went up throughout its first week. On March 29, 929,000 viewers watched the trial as it began just after 10:30 Eastern time. By Friday, the fifth day, MSNBC viewership figures for the morning portion had risen to 1.2 million viewers, according to Nielsen.

The figures are nothing close to interest to the 1995 O.J. Simpson trial. Roughly 50 million people watched the trial’s conclusion from their homes, a figure that may have been three times that size if the number of people watching it at work, at school or in airports or restaurants had been factored in.

The Chauvin trial is expected to last several weeks, and the three cable news networks are likely to continue broadcasting significant portions of it.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 4:30 p.m. ET

April 6, 2021, 4:30 p.m. ET

Reporting from Minneapolis

After a private conference with lawyers for both sides, Judge Peter Cahill unexpectedly sends jurors home for the day an hour earlier than usual. He says witness testimony will resume on Wednesday at 9:15 Central, when Sgt. Jody Stiger of the Los Angeles Police Department, a use-of-force expert called by prosecutors, will return to the stand.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 4:28 p.m. ET

April 6, 2021, 4:28 p.m. ET

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Officer Nicole Mackenzie, who trains Minneapolis police officers on providing medical care, said at the trial of Derek Chauvin that bystanders could make it easier for officers to miss signs that a detainee is in distress.Still image, via Court TV

Derek Chauvin’s lawyer appeared to make some of his strongest arguments yet on Tuesday when he questioned a Minneapolis police officer who had been called by prosecutors to testify about training officers on providing medical care.

The officer, Nicole Mackenzie, who is the medical support coordinator for the Minneapolis Police Department, agreed with Mr. Chauvin’s lawyer that a police officer could mistake gasping for air with breathing and that a hostile group of bystanders could make it more likely for a police officer to miss signs that a detainee was in distress.

The lawyer, Eric J. Nelson, has repeatedly sought to argue that the group of people who yelled at police officers as they saw Mr. Chauvin kneeling on George Floyd may have forced his attention away from Mr. Floyd’s worsening condition.

Officer Mackenzie said it could be “incredibly difficult” to provide medical treatment in front of a loud crowd, even if they were not interfering physically.

“If you had a very hostile or volatile crowd — it sounds unreasonable — but bystanders do occasionally attack E.M.S. crews,” she testified.

Prosecutors have argued that the people who witnessed Mr. Floyd’s arrest presented no threat to the officers and were simply distraught over what they saw. They called Officer Mackenzie to the stand to bolster their argument that Mr. Chauvin, who was fired from the department and is facing charges including murder, violated police policies that required him to administer care to people in his custody when it was safe to do so.

But when Mr. Nelson asked if the police policies that require officers to administer care are “contingent upon what’s going on at the scene at the time,” Officer Mackenzie agreed.

She also described what she said were the effects of “excited delirium,” a controversial diagnosis that is often ascribed to people who die in police custody. Officer Mackenzie said that people experiencing excited delirium could exhibit “superhuman strength” because they do not feel normal levels of pain.

Mr. Nelson also showed images from a training slide show that she delivered to officers on the use of naloxone, the overdose-reversing treatment often known by the brand name Narcan. In that training, Officer Mackenzie noted that only a small amount of fentanyl can have deadly effects.

Fentanyl and methamphetamine were found in Mr. Floyd’s system, and Mr. Nelson has argued that the drugs may have caused his death.

There were parts of Officer Mackenzie’s testimony that helped the prosecution.

As police officers were arresting Mr. Floyd in May, and he was telling them he couldn’t breathe, one officer said it takes “a lot of oxygen” to talk. But Officer Mackenzie testified that someone who is having trouble breathing could still be able to speak, and that officers should not assume someone can breathe because they are talking.

“Just because they’re speaking doesn’t mean they’re breathing adequately,” she said.

At the end of the officer’s testimony, Judge Peter A. Cahill told her that Mr. Nelson was planning to bring her back to testify when he begins to lay out Mr. Chauvin’s defense.

Officer Mackenzie was the eighth current or former member of the Minneapolis Police Department whom prosecutors have called to testify. She said that when she was a rookie, Mr. Chauvin had filled in as her training officer for a day when her regular trainer was out sick. Mr. Chauvin had also attended training that she provided to the department.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 4:23 p.m. ET

April 6, 2021, 4:23 p.m. ET

Reporting from Chicago

Prosecutors are now examining the officers’ actions last May during the arrest of George Floyd and their decision to place him on the ground, on his stomach, handcuffed. Sgt. Jody Stiger, an L.A.P.D. use-of-force trainer and expert, said that a kick from Floyd while handcuffed, visible on a police body-camera video, could have been an attempt to evade the officers’ grasp.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 4:08 p.m. ET

April 6, 2021, 4:08 p.m. ET

A Miami police officer taking part in a training exercise in 2018.
Joe Raedle/Getty Images

Much of Tuesday’s testimony has highlighted the training that the former Minneapolis police officer Derek Chauvin received. But one longtime issue in policing in Minneapolis and elsewhere is the difference between what officers learn in the academy and what they learn on the streets.

Law enforcement officials and criminal justice experts have said that while officers may learn things like de-escalation and community engagement in training, they can be highly influenced by whoever trains them on the job.

And sometimes those field-training officers may be from an earlier generation that employed a more aggressive approach. That divide has been a concern of Minneapolis police and city officials as they try to change the way their officers operate after the death of George Floyd.

Mr. Chauvin, who is facing murder charges after kneeling on Mr. Floyd’s neck for more than nine minutes, was a field-training officer. He had supervised two of the rookie officers involved in Mr. Floyd’s arrest.

“Every police agency has a mission statement, but the culture is what is accepted by leadership on a day-to-day basis,” Sean Hendrickson, an instructor at Washington State’s police academy, told The New York Times in an article last year. “That gets backed up by other officers and is extremely deep and very difficult to change.”

Some activists have argued that the Minneapolis police — and other police agencies — were so irreparably broken that no amount of new training can reform them. Others have expressed concern that officers do not receive proper or enough training.

Most states require fewer minimum training hours to become licensed as a police officer than they do for barbers or cosmetologists. As of last year, for example, New York State law mandates 1,000 hours of training for massage therapists, compared with around 700 hours for officers. Hawaii has no minimum requirements for police officers, but manicurists must train for 300 hours.

Becoming a police officer in Minneapolis requires first getting a peace officer license from the state, which entails as many as 1,050 hours of training. Once recruits obtain their licenses, they have to go through additional training run by the Minneapolis Police Department that includes 19 weeks in the academy.

After completing the academy, new officers spend five months on the streets with a field training officer, who is supposed to teach recruits how to translate what they learned in the academy to real-life situations. But current and former officers pointed to one of the first things that field training officers often say to new recruits: “Forget everything you learned in the academy.”

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 3:55 p.m. ET

April 6, 2021, 3:55 p.m. ET

Reporting from Chicago

Jody Stiger, a sergeant with the Los Angeles Police Department, is the first use-of-force expert witness from outside of the Minneapolis Police Department that the prosecution has called to testify against Derek Chauvin. Stiger’s experience as an instructor in the L.A.P.D. is extensive; he testified that he has trained close to 3,000 police officers in use-of-force tactics.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 4:04 p.m. ET

April 6, 2021, 4:04 p.m. ET

Reporting from Chicago

Sgt. Stiger says he has closely examined Chauvin’s actions last May during the arrest of George Floyd and come to a conclusion: “My opinion was that the force was excessive.”

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 2

April 6, 2021, 3:49 p.m. ET

April 6, 2021, 3:49 p.m. ET

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Los Angeles Police Sgt. Jody Stiger, a use-of-force expert, told jurors on Tuesday that the former police officer Derek Chauvin used excessive force on George Floyd during his arrest.Still image, via Court TV

Sgt. Jody Stiger of the Los Angeles Police Department took the stand on Tuesday and was expected to be the only outside expert to testify for the state about police training and use of force.

Asked directly about former Minneapolis police officer Derek Chauvin’s actions in the arrest of George Floyd, Sergeant Stiger was blunt: “My opinion was that the force was excessive.”

Sergeant Stiger, a former Marine, joined the Los Angeles Police Department in 1993, according to a spokeswoman for the department. He holds the rank of sergeant II and serves as an aide to the office of the Inspector General, the body that oversees the police department and conducts performance audits, reviews use-of-force incidents and handles complaints of officer misconduct. He is the only sworn officer on staff.

He is also president of the Oscar Joel Bryant Foundation, which represents Black officers and civilian employees of the Los Angeles Police Department.

Sergeant Stiger served as a tactics instructor for in-service training for Los Angeles police officers for six years, during which he provided training regarding use-of-force policy and state law to about 3,000 officers, he said during his testimony.

He said he has conducted more than 2,500 reviews while working with the department and has consulted several entities on use-of-force reviews.

Sergeant Stiger was paid a flat fee of $10,000, as well as a trial fee, to review reports, video footage of the incident, training policies and other materials and ultimately make a judgment about whether the use of force by Mr. Chauvin was appropriate.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 16

April 6, 2021, 3:29 p.m. ET

April 6, 2021, 3:29 p.m. ET

Reporting from Minneapolis

The defense has indicated it will recall Officer Nicole Mackenzie, the medical support coordinator for the Minneapolis Police Department, during Derek Chauvin’s portion of the trial, suggesting that Eric Nelson, Chauvin’s lawyer, believes her testimony was helpful to his case.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 3:23 p.m. ET

April 6, 2021, 3:23 p.m. ET

Reporting from Minneapolis

Eric Nelson, Derek Chauvin’s lawyer, ended his cross examination of Officer Nicole Mackenzie, the police department’s medical trainer, with some strong points for the defense. She told him that it’s very difficult to focus on the patient when you have loud things happening around you, that it’s more difficult to assess a patient, and it makes it possible that you might miss signs of problems. This could all be used to argue that George Floyd’s death was manslaughter — more of a mistake on Chauvin’s part than a depraved crime.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 16

April 6, 2021, 3:24 p.m. ET

April 6, 2021, 3:24 p.m. ET

Reporting from Minneapolis

The prosecution took a risk by calling so many use-of-force witnesses; now some of them are coming very close to bolstering key aspects of the defense’s case.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 3:04 p.m. ET

April 6, 2021, 3:04 p.m. ET

Reporting from Chicago

In his questioning of Officer Nicole Mackenzie, the Minneapolis Police Department’s medical response trainer, Derek Chauvin’s lawyer returns to a line of questioning that he has raised with several other expert witnesses, suggesting that the shouting bystanders at the scene last May were a factor in Chauvin’s decision to continue restraining George Floyd.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 2:57 p.m. ET

April 6, 2021, 2:57 p.m. ET

Reporting from Minneapolis

As police officers were arresting George Floyd and he was telling them he couldn’t breathe, video captured one officer telling him it takes “a lot of oxygen” to talk. But medical experts have said people can be struggling to breathe and still speak. Officer Nicole Mackenzie, who trains Minneapolis police officers in medical treatment, backed that up from the stand, testifying, “Just because they’re speaking doesn’t mean they’re breathing adequately.”

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 2:36 p.m. ET

April 6, 2021, 2:36 p.m. ET

Reporting from Minneapolis

Now testifying after the court’s lunch break is Officer Nicole Mackenzie, the medical support coordinator for the Minneapolis Police Department, who is expected to testify about officers providing medical treatment to people who are having a crisis. She is the eighth member of the department to testify for the prosecution in this trial.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 2:18 p.m. ET

April 6, 2021, 2:18 p.m. ET

The Rev. Al Sharpton, center, prayed with relatives of George Floyd on Tuesday outside of the courthouse where Derek Chauvin is on trial.
Joshua Rashaad McFadden for The New York Times

Relatives of George Floyd prayed outside the courthouse with the Rev. Al Sharpton on Tuesday, asking God for “justice” from the jury and for strength to continue closely watching the trial taking place on the 18th floor of the building behind them.

“Give this family strength that they can bear the recurring sight of seeing their brother with a knee on his neck,” Mr. Sharpton said. “A knee that represents the perpetual knee on the necks of all Black Americans.”

As he spoke, testimony continued inside the courtroom in the trial of Derek Chauvin, who has been charged with murder in George Floyd’s death. Ben Crump, a lawyer for the Floyd family, said the family had been told that autopsy photographs may be shown in court on Tuesday.

Prosecutors have already shown several graphic videos of the police confronting Mr. Floyd and Mr. Chauvin kneeling on him for more than nine minutes. Mr. Sharpton said he was praying for everyone watching the trial who was “suffering with” the Floyd family.

In addition to Mr. Crump and Mr. Sharpton, several high-profile Black politicians and activists accompanied the Floyd family. Among them were David A. Paterson, the former governor of New York; Gwen Carr, the mother of Eric Garner, who died in 2014 when a New York police officer put him in a chokehold; and Ray McGuire, who is running for mayor in New York and has secured Ms. Carr’s endorsement.

As two law enforcement officials in camouflage watched from a roof of the courthouse, several relatives of Mr. Floyd bowed their heads in prayer.

Afterward, Philonise Floyd, a brother of George’s, put his arm around Ms. Carr.

“We and Ms. Gwen Carr, after we get the verdict and we get this conviction, we’ll be able to breathe,” he said.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 1:56 p.m. ET

April 6, 2021, 1:56 p.m. ET

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Lt. Johnny Mercil of the Minneapolis Police Department said Tuesday that neck restraints are sometimes allowed but that the former officer Derek Chauvin’s use of the technique on George Floyd was not appropriate.Still image, via Court TV

Lt. Johnny Mercil, the second witness of the day, is a veteran of the Minneapolis Police Department, a practitioner of Brazilian jiu-jitsu and a use-of-force instructor who has trained hundreds of police officers.

His testimony focused on a crucial argument for the prosecution: that Derek Chauvin’s actions last May were not consistent with how officers have been taught to restrain people who are resisting arrest.

Steve Schleicher, a prosecutor, displayed a picture of Mr. Chauvin pinning George Floyd to the ground and asked, “Is this an M.P.D.-trained neck restraint?”

“No, sir,” Lieutenant Mercil responded.

The lieutenant, who is currently on medical leave from the Minneapolis Police Department, is the seventh member of the department to testify for the prosecution in Mr. Chauvin’s trial.

But Eric J. Nelson, a lawyer for Mr. Chauvin, countered with a line of questioning emphasizing the unpredictability of people who are being taken into custody, the possibility that they could stop resisting arrest and then suddenly become violent, and the challenge for police officers in assessing a situation as circumstances shift.

He suggested that Mr. Chauvin’s knee was not the cause of Mr. Floyd’s unconsciousness, and asked Lieutenant Mercil whether a restraint requires pressure on both sides of the neck for the person to go unconscious. “That is what we teach, yes,” he said.

Mr. Nelson repeatedly invoked the chaotic scene around Mr. Chauvin last May, asking Lieutenant Mercil whether bystanders yelling insults at an officer would “reasonably tend to rise alarm in an officer.” He agreed that they would.

Mr. Schleicher, the prosecutor, then asked: “And if they’re saying, ‘Get off him, you’re killing him,’ should the officer also take that into account and consider whether their actions need to be reassessed?”

“Potentially, sir, yes,” Lieutenant Mercil said.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 1:24 p.m. ET

April 6, 2021, 1:24 p.m. ET

Reporting from Chicago

The testimony from Lt. Johnny Mercil, a use-of-force trainer with the Minneapolis Police Department, has wrapped up, and the court is taking a break for lunch.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 16

April 6, 2021, 12:52 p.m. ET

April 6, 2021, 12:52 p.m. ET

Reporting from Minneapolis

Questions from the defense to Lt. Johnny Mercil, a use-of-force trainer with the Minneapolis Police Department, about whether unconscious people can suddenly regain consciousness and fight back are laying the groundwork to argue that Derek Chauvin was behaving reasonably when he continued to restrain George Floyd for more than nine minutes, even after he lost consciousness.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 16

April 6, 2021, 12:54 p.m. ET

April 6, 2021, 12:54 p.m. ET

Reporting from Minneapolis

The fact that Lt. Mercil keeps agreeing with the defense lawyer on this line of questioning could present a problem for the prosecution.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 12:44 p.m. ET

April 6, 2021, 12:44 p.m. ET

Reporting from Minneapolis

Defense lawyer Eric Nelson seems to be laying the foundation to argue that Derek Chauvin’s knee on George Floyd’s neck was not a neck restraint and did not cause Floyd to go unconscious. He asked use-of-force trainer Lt. Johnny Mercil whether a restraint requires pressure on both sides of the neck for the person to go unconscious. “That is what we teach, yes,” Mercil said.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 12:45 p.m. ET

April 6, 2021, 12:45 p.m. ET

Reporting from Minneapolis

Mercil also said that generally it takes less than 10 seconds for someone to go unconscious because of a neck restraint. That’s likely a point that Nelson will use to say that it took Floyd longer than 10 seconds to go unconscious.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 16

April 6, 2021, 12:39 p.m. ET

April 6, 2021, 12:39 p.m. ET

Reporting from Minneapolis

Derek Chauvin’s defense lawyer, Eric Nelson, has just asked Johnny Mercil, a lieutenant and use-of-force trainer with the Minneapolis Police Department, if people on drugs can display “more strength than they would have otherwise.” Superhuman strength is associated with excited delirium, a controversial diagnosis that is often cited in autopsies after deaths in police custody.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 12:37 p.m. ET

April 6, 2021, 12:37 p.m. ET

Prosecutors presenting police guidance on the use of neck restraints during the trial of the former officer Derek Chauvin.
Still image, via Court TV

Even as several members of the Minneapolis Police Department have criticized Derek Chauvin’s use of force against George Floyd, they have acknowledged that using force is a necessary part of policing. And data shows that reports of force are extremely rare, although the outcome can sometimes be significant.

Since 2018, there have been 14 reported incidents of officers’ using neck restraints in which the person it was being used on became unconscious, according to data from the department. The most recent incident was in February 2020 in which a 20-year-old Black male was restrained during a traffic stop for “verbal noncompliance,” the data said. Since 2012, there had been 310 instances in which neck restraints were used and the subject did not lose consciousness.

A central question for jurors in this trial will be whether it was appropriate for Mr. Chauvin to kneel on Mr. Floyd’s neck for more than nine minutes. Johnny Mercil, a Minneapolis police lieutenant who provided use-of-force training to Mr. Chauvin, testified that officers were trained to “use the lowest level of force possible in order to meet those objectives.”

In many ways, this phase of the trial is putting police tactics on trial. Minneapolis residents, particularly African-Americans, have been highly critical of the Police Department, which they say has brutalized their communities. Since 2015, the Police Department has used force against Black residents at seven times the rate that it did against white residents, according to a New York Times analysis of police data last year.

About 20 percent of Minneapolis’s 430,000 residents are Black, but nearly 62 percent of the time that officers used force, it was against Black residents, according to the data.

Police officials argue that although the use of force may get a lot of attention, it is exceedingly rare. The data shows that there have been 4.3 million calls for service since 2008, but force was reported in just 13,472 of those instances, or just .31 percent of the time.

For residents who live in heavily policed areas, however, constant harassment by the police, even when force is not used, has left a bad impression. And shocking cases like Mr. Floyd’s can tend to overshadow the fact that force might be rarely used.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 11:44 a.m. ET

April 6, 2021, 11:44 a.m. ET

Reporting from Chicago

Johnny Mercil, a lieutenant with the Minneapolis Police Department, is explaining the use-of-force strategies that he teaches to police officers. His testimony here repeats a similar theme from earlier expert witnesses: When trying to control a subject, officers are trained to “use the lowest level of force possible in order to meet those objectives,” he says.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 11

April 6, 2021, 11:55 a.m. ET

April 6, 2021, 11:55 a.m. ET

Reporting from Chicago

The prosecution is focusing its questions to Mercil on when it is appropriate for a police oficer to use a neck restraint on a suspect, as Derek Chauvin did on George Floyd. When shown a picture of Chauvin pinning Floyd to the ground and asked, “Is this an M.P.D.-trained neck restraint?” the lieutenant responds, “No, sir.”

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 11:39 a.m. ET

April 6, 2021, 11:39 a.m. ET

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Sgt. Ker Yang, a crisis intervention coordinator with the Minneapolis Police Department, testified on Tuesday that officers have time to slow down, re-evaluate and reassess while arresting someone.Still image, via Court TV

Lawyers for both the prosecution and the defense continued to argue on Tuesday over whether Derek Chauvin violated police policy when he knelt on George Floyd, asking a range of questions to the day’s first witness, a crisis intervention coordinator with the Minneapolis Police Department.

Prosecutors called the coordinator, Sgt. Ker Yang, 49, to the stand and walked through the various decisions that officers are expected to make while on the job. Steve Schleicher, a prosecutor, emphasized in his questions that the police are supposed to constantly re-evaluate a situation and act accordingly, to which Sergeant Yang agreed.

“When we talk about fast-evolving situations, I know that they do exist, they do happen,” Sergeant Yang testified. But in many situations, he added, “We have the time to slow things down and re-evaluate and reassess.”

His comments echoed those of Chief Medaria Arradondo, who on Monday testified that while Mr. Chauvin’s initial efforts to restrain Mr. Floyd may have been reasonable, he had violated policy by continuing to kneel on Mr. Floyd for more than nine minutes.

Mr. Schleicher noted on Tuesday that Mr. Chauvin had participated in a 40-hour crisis intervention training course in 2016.

Eric J. Nelson, Mr. Chauvin’s lawyer, pressed his argument that bystanders at the scene of an arrest can have a large effect on how an officer acts, and that an officer can “look bad” even while using force that is lawful. He also emphasized that officers are not supposed to remain solely focused on someone they are arresting, but are also supposed to consider other parts of their surroundings.

“It’s not just one small thing that you’re focused only on the subject that you’re arresting,” Mr. Nelson said. “You’re taking in a lot of information and processing it all kind of simultaneously through this critical decision-making model.” Sergeant Yang agreed.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 11:20 a.m. ET

April 6, 2021, 11:20 a.m. ET

Reporting from Minneapolis

The next witness is Johnny Mercil, a police lieutenant who is currently on medical leave from the Minneapolis Police Department. He is a use-of-force trainer, and early in his career was assigned to the Third Precinct, whose station house burned down early in the protests following George Floyd’s death last year. His testimony will continue the focus on the training given to Minneapolis police officers.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 11:24 a.m. ET

April 6, 2021, 11:24 a.m. ET

Reporting from Minneapolis

He teaches officers Brazilian jiu jitsu and other hands-on tactics for subduing suspects.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 11:13 a.m. ET

April 6, 2021, 11:13 a.m. ET

Reporting from Minneapolis

It’s interesting to see Derek Chauvin’s defense lawyer focus on how, as the intensity of a situation grows, the risk to an officer increases. I spoke with a former high-level Minneapolis police commander last year, and he told me that the constant focus among police officers on their safety could sometimes lead to actions that put them at odds with the communities they serve. His main point was that it’s a fine line between keeping oneself safe as an officer, but also not seeing everything and everyone around you as a threat or an enemy.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 10:59 a.m. ET

April 6, 2021, 10:59 a.m. ET

Reporting from Minneapolis

The defense lawyer, Eric Nelson, is now questioning Sgt. Ker Yang, the Minneapolis Police Department’s crisis intervention training coordinator, and he is trying to establish that police tactics can sometimes get messy, but they’re still allowed. “They still may be lawful even if they look bad?” Nelson asked. “Yes sir,” Yang responded. Of course, jurors will have to determine whether kneeling on George Floyd’s neck for more than nine minutes was something that just “looked bad” or whether it was unlawful.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 10:37 a.m. ET

April 6, 2021, 10:37 a.m. ET

Reporting from Minneapolis

The first witness called by prosecutors today is Sgt. Ker Yang, 49, a crisis intervention training coordinator with the Minneapolis Police Department. Prosecutors will likely use his testimony to try to show that Derek Chauvin had been trained in how to safely respond to people who were having various kinds of crises.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 12

April 6, 2021, 10:52 a.m. ET

April 6, 2021, 10:52 a.m. ET

Reporting from Minneapolis

Prosecutors seem to be trying to establish with Sgt. Yang that the officers arresting George Floyd were trained to assess the situation and should have gone from using force against Floyd to trying to provide him with medical attention.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 9:59 a.m. ET

April 6, 2021, 9:59 a.m. ET

Reporting from Minneapolis

The judge is not going to rule today on whether Morries Hall, the friend of George Floyd’s who was with him in the moments before his death in May, can be forced to testify. The judge will likely rule later this week. Derek Chauvin’s lawyer has many questions for Mr. Hall, but almost all of them have the potential to incriminate him, and Mr. Hall has said he would invoke his Fifth Amendment right against self-incrimination.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 9:39 a.m. ET

April 6, 2021, 9:39 a.m. ET

Reporting from Minneapolis

Before the jury is brought in this morning, court starts with an appearance from Morries Lester Hall, a friend of George Floyd’s who was in the car with him on May 25, the day Floyd died, in the moments before the police arrived. His lawyer says he does not want to testify and would invoke his Fifth Amendment right to not incriminate himself. This hearing is over whether he can be forced to testify against his will. He is currently being held in jail on charges unrelated to Floyd’s death and is appearing on video.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 9:45 a.m. ET

April 6, 2021, 9:45 a.m. ET

Reporting from Minneapolis

Derek Chauvin’s defense lawyer has outlined a long list of questions that he wants to ask Hall. Among them are questions about his interactions with Floyd in Cup Foods, about Floyd’s use of drugs, about Hall’s decision to leave the state after Floyd’s death, and much more. Almost all of those things have the potential to incriminate Hall.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 9

April 6, 2021, 9:34 a.m. ET

April 6, 2021, 9:34 a.m. ET

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Morries Hall, a friend of George Floyd who was with him when he was arrested, is hoping to avoid testifying. On Tuesday, Mr. Hall’s legal team stated he planned to invoke his Fifth Amendment right against self-incrimination.Still image, via Court TV

Morries Lester Hall, a friend of George Floyd’s who was in a car with him on May 25, moments before the police pulled Mr. Floyd out of the car and pinned him to the ground, is hoping to avoid testifying in the murder trial of Derek Chauvin.

At a hearing on Tuesday morning over whether Mr. Hall must testify, his lawyer said that testifying about any of his actions on May 25 had the potential to incriminate him, and that Mr. Hall planned to invoke his Fifth Amendment right against self-incrimination. Mr. Hall, who is currently in jail on charges unrelated to Mr. Floyd’s death, appeared in court by video conference, though he spoke only to spell his name and confirm that he had conferred with his lawyer.

Judge Peter A. Cahill, who is overseeing the trial of Mr. Chauvin, did not rule on whether Mr. Hall must testify, but he ordered Mr. Chauvin’s lawyer to draft a list of questions by Thursday that Mr. Hall might be able to answer without incriminating himself. Videos from the scene show that Mr. Hall was sitting in the passenger seat of a car when the police initially confronted Mr. Floyd, shortly before he was pinned to the ground and died.

Adrienne Cousins, Mr. Hall’s lawyer, said that both prosecutors and Mr. Chauvin’s lawyer, Eric J. Nelson, had subpoenaed Mr. Hall, though Mr. Nelson seemed more interested in calling him to the stand. Mr. Nelson said in court that he wanted to ask Mr. Hall a range of questions, including about whether he had given Mr. Floyd drugs, about the fake $20 bill that a convenience store clerk said Mr. Floyd used, and about why Mr. Hall left Minnesota after Mr. Floyd had died.

Ms. Cousins said that all of those questions could incriminate her client, and Judge Cahill largely seemed to agree. But the judge said there may be a narrow range of questions — possibly on how Mr. Floyd appeared to be acting in the car before the police arrived — that Mr. Hall might be able to answer without incriminating himself. Ms. Cousins strenuously disagreed, saying that even acknowledging that Mr. Hall was in the car with Mr. Floyd on May 25 could be used against him if he were to be charged with a crime based on his actions that day.

For their part, prosecutors seemed most worried about the prospect that Mr. Hall would take the stand and invoke his Fifth Amendment right in front of the jury, perhaps making them further question Mr. Floyd’s actions that day or making them concerned about what is being withheld.

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April 6, 2021, 9:27 a.m. ET

April 6, 2021, 9:27 a.m. ET

The Hennepin County Government Center, where on Monday the prosecution began laying out the evidence that Derek Chauvin’s kneeling on George Floyd’s neck for more than nine minutes violated department policy.
Joshua Rashaad McFadden for The New York Times

The first week of the former police officer Derek Chauvin’s trial was emotional, marked by gut-wrenching eyewitness accounts, combative exchanges and vivid videos. But according to Justin Hansford, a law professor at Howard University, Monday marked the start of a more critical part of the trial.

The prosecution began laying out the evidence that Mr. Chauvin’s decision to kneel on George Floyd’s neck for more than nine minutes violated department policy and that his actions led directly to Mr. Floyd’s death on May 25. That’s the “meat” of the prosecution’s case and is the only evidence that the jury can use to reach a verdict, said Mr. Hansford, who has been watching the trial daily.

Prosecutors should have started with “a more substantive argument early on, rather than an emotional one” because that is what the jurors are asked to consider in their decision, Mr. Hansford said. “We should be watching the expert testimony closely because that will be grounds” for the verdict, he said.

On Monday, the jurors heard none of the harrowing accounts of Mr. Floyd’s arrest. Instead, the prosecution guided the Minneapolis police chief, Medaria Arrodondo, through more than two hours of questions about the law, police training and standards. Prosecutors followed that with questions to the Police Department’s former training director about how often Mr. Chauvin would have received guidance on tactics such as restraining suspects, use of force and medical aid.

Chief Arrodondo testified that Mr. Chauvin violated the department’s policy when he pinned Mr. Floyd for more than nine minutes and failed to render aid.

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 1

April 6, 2021, 5:00 a.m. ET

April 6, 2021, 5:00 a.m. ET

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Chief Medaria Arradondo testified Monday that the former officer Derek Chauvin should have halted his use of force to restrain George Floyd after Mr. Floyd had stopped resisting.Still image, via Court TV

Unequivocal condemnation from the chief of the Minneapolis Police Department has pushed the trial of Derek Chauvin, the former officer charged in the death of George Floyd, into new territory.

Questions about whether Mr. Chauvin violated department policy by keeping his knee on Mr. Floyd for nine and a half minutes will remain important as the trial moves forward on Tuesday. The judge, Peter A. Cahill, said he would limit the number of police officers who could testify about use of force, though one more officer is expected to answer questions on the crucial topic.

On Monday, Chief Medaria Arradondo rebuked Mr. Chauvin — saying he pinned Mr. Floyd for too long and failed to render aid — in a rare example of a police chief testifying against a police officer. Though Mr. Chauvin’s restraints may have been justified at first, “Once Mr. Floyd had stopped resisting, and certainly once he was in distress and trying to verbalize that, that should have stopped,” the chief said.

Other witnesses included an emergency room doctor and veteran officer.

Dr. Bradford T. Wankhede Langenfeld, who attempted to save Mr. Floyd’s life at a hospital for about 30 minutes before declaring his death, said he believed that asphyxia, or the deprivation of oxygen, was one of the more likely causes of death. The prosecution has sought to validate that claim, while the defense has pointed to complications from drug use and a heart condition.

Inspector Katie Blackwell, a veteran police officer in Minneapolis, told jurors that officers should move suspects who are facedown and handcuffed “as soon as possible” because the position can make it difficult to breathe. Mr. Floyd was kept on his stomach even after he lost consciousness.

Mr. Chauvin’s lawyer, Eric J. Nelson, argued that officers sometimes have to juggle multiple things when applying force, such as possible threats from bystanders. Regarding Mr. Floyd’s cause of death, Mr. Nelson got Dr. Wankhede Langenfeld to confirm that drug use could cause asphyxia.

Ultimately, Monday’s testimony may prove problematic for the defense. The criticism by Chief Arradondo, in particular, could encourage the jury to break from the norm of giving police officers the benefit of the doubt when it comes to split-second decisions on when, and how, to apply force.

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April 5, 2021, 7:00 p.m. ET

April 5, 2021, 7:00 p.m. ET

Nekima Levy Armstrong, a civil rights lawyer, speaking at a rally in Minneapolis in November.
Joshua Rashaad McFadden for The New York Times

During his testimony on Monday, Medaria Arradondo, the Minneapolis police chief, said that he learned about the widely seen bystander video when a community member called him close to midnight after George Floyd’s death and said, “Chief, have you seen the video of your officer choking and killing that man at 38th and Chicago?”

Nekima Levy Armstrong, a civil rights lawyer, said in an interview on Monday that she was the community member who had that conversation with the chief about 10 months ago. She watched his testimony in the case of Derek Chauvin, the former officer accused of murder in Mr. Floyd’s death, and said she was pleased.

“He set a powerful example that police chiefs across the nation should follow when they know that their officers have violated people’s human rights and constitutional rights,” Ms. Armstrong said.

Residents and political leaders have been intensely debating the future of the city’s police department, with some activists and City Council members advocating the dismantling of the department and creating a new public safety agency that would oversee law enforcement. Some have said that the head of the new agency should not be a police officer, but Ms. Armstrong said that Chief Arradondo’s testimony instilled confidence in her that he should continue to lead law enforcement in Minneapolis.

“I think the fact that Chief Arradondo — not once, but twice — has been willing to break that blue wall of silence is incredibly important,” she said.

Other activists were not as impressed with the chief. D.A. Bullock is a local activist and filmmaker who said he favored defunding and dismantling the Police Department, and eventually abolishing it all together. He said he was disturbed that Chief Arradondo suggested that there were times when it was appropriate for officers to place their knees on the necks of suspects to get them under control.

That, Mr. Bullock said, “means to me that they are going to continue the practice of putting their knees on Black men’s necks.”

Like other supporters of efforts to defund the police, Mr. Bullock said he thought that Chief Arradondo was well intentioned. But he argued that the problems within the department were so systemic that there was little the police chief could do to make policing better.

“I encourage people again to look at the policy and not look at his performance,” Mr. Bullock said. “I don’t feel very confident in that testimony about actual changes in the Police Department.”

Expert Witness Says Chauvin’s ‘Force Was Excessive’ 44

April 5, 2021, 4:27 p.m. ET

April 5, 2021, 4:27 p.m. ET

Prosecutors quizzed Medaria Arradondo, the Minneapolis police chief, on Monday about his department’s standards and training during the trial of former officer Derek Chauvin.
Still image, via Court TV

In testimony that often seemed more like he was teaching a criminal law class, the Minneapolis police chief, Medaria Arradondo, spent more than two hours on Monday detailing the training his officers must complete and the standards they must comply with. Navigating jargon and statutes, his testimony in former officer Derek Chauvin’s trial is crucial in determining whether Mr. Chauvin is criminally responsible for George Floyd’s death.

The prosecution must show that Mr. Chauvin “acted unreasonably and out of the bounds” of his training and the standards set by Minnesota, said David Schultz, a law professor at the University of Minnesota. Prosecutors need to show he “went rogue.” If the defense can prove that Mr. Chauvin followed all protocols, then “the case is all over” for the prosecution, Mr. Schulz said.

Mr. Arradondo fired Mr. Chauvin and backed an F.B.I. investigation shortly after Mr. Floyd’s death, calling it a “murder.” His prior comments will very likely face scrutiny when Mr. Chauvin’s lawyer, Eric J. Nelson, cross-examines him.

Proving that Mr. Chauvin broke policy is one of the two most important tasks for prosecutors, Mr. Schultz said. The other is proving that Mr. Floyd died as a direct result of Mr. Chauvin kneeling on his neck and restraining him. The defense has argued instead that Mr. Floyd died of a combination of factors, including an overdose, and that Mr. Chauvin was following Minnesota policing standards.

Minnesota has fairly clear and high standards for police officers, and unlike other states, it licenses and regulates its police officers, Mr. Schultz said. The defense will remind the jury that police officers across the country have statutory authorization to use force by way of a Supreme Court decision on qualified immunity, Mr. Schultz said.

“What Arradondo and the other police officers last week are doing is saying that Chauvin wasn’t a responsible police officer” based on the standards and training he had received, Mr. Schultz said. “This is what they have to do to show he engaged in criminal activity” and therefore lost his qualified immunity, he said.