MINNEAPOLIS — “I’m about to die,” George Floyd said as he lay facedown beneath the knee of Minneapolis Police Officer Derek Chauvin, who debated with his partner, Thomas Lane.

“Should we roll him on his side?” Lane asked.

“No, staying put where we got him,” Chauvin replied.

“I am worried about excited delirium or whatever,” Lane said.

By the time Chauvin removed his knee from Floyd’s neck, Floyd had no pulse.

In the weeks since Floyd’s death was captured on video, protests have reignited calls for police reform and a deeper look at use-of-force training nationwide.

In several police departments, that training comes from a Minnesota company called the Force Science Institute, which remains popular with agencies despite, experts say, a long history of disputed concepts like “excited delirium” to justify encounters that sometimes turn deadly.

Its critics include a former Justice Department official and the head of a top policing group, who worry that the institute’s offerings are ineffective and foster fear among officers that can lead to unnecessary force.

Before this article was initially published online on Friday, the institute said it had a weeklong training session with the Los Angeles Police Department scheduled for November. After publication, the LAPD told The Times in a statement that the training was “erroneously advertised” and had not been approved.

“The department is not hosting this planned event, nor will it be hosting any future trainings” by Force Science Institute, the statement said. The LAPD “does not sponsor, endorse or support the Force [Science] Institute (FSI), and their curriculum is not accredited by the LAPD,” the department said.

LAPD Training Director Luann P. Pannell explained in an interview that the department is going “in a different direction,” and “every training effort is going to be clearly evaluated and put into alignment with where the department is going.”

According to Pannell, fewer than 70 LAPD officers have attended Force Science training since 2012, with just two attending last year. She also pointed out that LAPD officers attended the institute’s two-day course, which focuses on human behavior such as reaction time and memory, not the institute’s de-escalation or tactical training.

The LAPD was unable to provide a dollar amount for how much it has spent on the institute’s courses.

A listing for the November program on the Force Science website has been updated and no longer mentions the LAPD.

The institute’s de-escalation course includes training officers how to respond to “excited delirium.” The company and others describe that condition as a frenzied state that can quickly turn violent.

Many medical experts question whether it exists. The condition is not recognized by the American Medical Assn., the World Health Organization or the American Psychiatric Assn.

But the term has been embraced by FSI, which was founded in 2004 by William Lewinski. A former college professor in Minnesota, Lewinski has billed himself and his institute as a leading source of research on policing, with legal expertise for officers accused of using excessive force.

The company has trained officers nationwide, including in Los Angeles and Minnesota, and argued against local reforms to use-of-force policies in 2018 after the fatal shooting of an unarmed Black man in California.

Since 2005, FSI has written extensively on excited delirium, including more than 20 web articles exploring the dangers of the condition for police and suspects.

The institute has long drawn criticism from academics and police reform advocates who say the group uses psychology in questionable ways to explain police encounters that can turn deadly. Critics say FSI overuses concepts like “inattentional blindness,” in which people fail to see what’s right in front of them, to defend a variety of police situations gone wrong.

Lewinski has repeatedly come under fire for his prolific paid work defending officers in court, including in high-profile cases like the 2009 killing of Oscar Grant, who was fatally shot by transit police in Oakland.

FSI remains popular with law enforcement. In 2018, the institute was hired by the International Union of Police Assns., the country’s largest police union, to lead a national training seminar. The police union did not respond to requests for comment.

Last fall, nearly 70 law enforcement personnel from across the country gathered at the training center for the St. Paul Police Department in Minnesota for FSI’s eight-hour de-escalation course, which included how to handle excited delirium.

Among the attendees of the class, which cost $295 per person, were three Minneapolis Police Department officers, according to department spokesman John Elder, who declined to share a list of approved external training or to say whether the department works with FSI.

A separate source confirmed to The Times that none of the three Minneapolis officers who attended were among the four fired in connection with Floyd’s killing.

In a four-page statement to The Times, the institute declined to provide specific figures on how many officers or police departments it has trained over the years and said it did not have a formal relationship with the LAPD at this time.

FSI also reiterated its commitment “to training officers to recognize and safely de-escalate threats before any force becomes necessary.”

“We hope that our research will lead to the development of tactics and strategies that reduce the need for force,” it added.

However, at least two departments have pulled back on FSI training amid criticism from advocates of police reform. In 2017, the Rochester Police Department in New York canceled plans to send 10 officers to a five-day training session sponsored by the local police union. Advocates of police reform had criticized the use of $15,000 in city funds for the event, which they believed was aimed at helping officers justify shootings.

A two-day program for Ohio State University’s police division was canceled in February after a petition garnered nearly 500 signatures from the campus community.

“This language is incredibly disturbing and suggests that this class is little more than a training in how to get away with police brutality,” the petition reads.

In both instances, critics cited a 2015 article by the New York Times that questioned Lewinski’s credentials and his work testifying and consulting for officers in use-of-force lawsuits.

In a statement to the Los Angeles Times, FSI wrote that it was disappointed by Ohio State’s decision to cancel the training.

Among the institute’s critics is Christy Lopez, a professor at Georgetown University Law Center in Washington and an attorney who litigated police misconduct with the Justice Department during the Obama administration. Lopez also oversaw reforms at the Oakland Police Department in 2003.

She counts FSI as part of an “insidious” trend in police training in which “pseudoscientific studies” are used to justify excessive force on the streets and in courtrooms, allowing officers to evade accountability for misconduct.

Lopez attended an FSI training session while working at the Justice Department and called it “the Bill Lewinski show.”

“He paces around, talks about how he’s a black belt, he does mock karate moves,” she said, comparing Lewinski to animal trainer Joe Exotic, who was featured in the “Tiger King” Netflix documentary series.

Although students may “eat it up,” Lopez says, the danger is real. “That is a big part of creating this undue fear among officers that make them overreact in situations and make them afraid to not take the time to not kill somebody.”

Chuck Wexler, director of the Police Executive Research Forum, a Washington-based nonprofit founded in 1976 that works closely with law enforcement agencies and policymakers, said FSI training “wasn’t helpful to reducing use of force.”

“A lot of cops would go to Force Science and were led to believe the concepts were evidence-based.... We just felt like, too often, their programs lacked any kind of quality control,” he said.

Chauvin, the officer who kneeled on Floyd’s neck, has been charged with manslaughter and second-degree murder. The three other officers on scene, including Lane, are charged with aiding and abetting.

Lane’s lawyer, Earl Gray, told The Times in an interview that his client learned the term “excited delirium” in his work at juvenile detention centers before becoming an officer and that it was “extremely important” to his defense.

Previewing his defense argument, Gray said that the day Floyd was killed was Lane’s fourth as an officer, and that while his reference to excited delirium in questioning whether Floyd should be turned over demonstrated an attempt to intervene, the expectation that Lane should physically stop Chauvin, his senior and a field training officer, was unreasonable.

Lawyers for Chauvin and former Officer Tou Thao, who was also charged in the Floyd case, did not respond to requests for comment. Thomas Plunkett, who represents former Officer J. Alexander Kueng, declined to comment.

A debate over training had been brewing in Minneapolis a month before Floyd’s death sparked national protests against police brutality. In April, the Minneapolis Police Department and mayor instituted a ban on “fear-based, warrior-style” training for its police force. But that ban did not specifically mention FSI.

Lewinski’s relationship with the Minneapolis Police Department dates to 1990, when he trained rookies at the academy for three years. In the decades since, he has conducted special training sessions for the department and, in 2007, was invited to discuss lethal force with the chiefs of the Minneapolis and St. Paul police departments.

St. Paul Police Department spokesman Sgt. Mike Ernster said no St. Paul officers attended the November 2019 FSI de-escalation training, and it was the only time, to his knowledge, that the institute had conducted training at the department.

“We do not have a contract or consult with Force Science Institute,” he said.

The institute offers several types of training, including a popular weeklong use-of-force course. Participants in that program are certified as FSI analysts, a title that appears on more than a hundred LinkedIn profiles belonging to former and current police officers, defense attorneys and consultants ranging from police instructors to expert witnesses for hire.

While the institute bills itself as nonpartisan, it recently sided with police unions against efforts to revamp California’s use-of-force policy after the 2018 fatal police shooting of Stephon Clark, an unarmed Black man in Sacramento. The 2019 legislation requires law enforcement to use deadly force only when “necessary,” instead of when “reasonable,” and has gotten renewed attention amid efforts to set national guidelines for use of force.

The institute criticized an early 2018 version of the bill, writing in a blog post that it would create “far greater hazards for officers and their agencies” and failed to “reflect an understanding of deadly force realities.” A Facebook photo in March 2019 showed Lewinski in the California Capitol with a caption noting that he was “staying busy this week making rounds with legislators.”

FSI was not listed as a lobbyist on the final bill and did not address whether it engages in lobbying generally as an organization.

By the institute’s own count, Lewinski had served as an expert witness in “over 200 coroner’s inquests, grand juries, criminal and civil cases and arbitration hearings” as of 2018. Among them: several lawsuits against LAPD officers, dating to 2002, in which Lewinski was hired to testify as an expert.

Those cases were handled by the police litigation unit of the Los Angeles city attorney’s office. The head of that unit, Cory Brente, delivered a keynote address at an institute conference in October 2018 on “vital strategies for preparing police officers and expert witnesses to maximize trial success in use-of-force cases,” according to an FSI Facebook post.

The city attorney’s office declined to make Brente available for an interview or provide a copy of his presentation. In a statement, spokesman Rob Wilcox wrote that the office continually reviews its slate of expert witnesses.

“To the best of our knowledge, Mr. [Lewinski] has not been retained by our office for several years,” Wilcox wrote.

Brente defended the LAPD in two use-of-force lawsuits last year — one in which Alex Aguilar, who was suspected of drug possession, died after being hit with a Taser five times during a strip search, and one in which Omar González was fatally shot in the back twice during a car pursuit. A year earlier, Brente represented one of the officers involved in the González case in another fatal shooting, that of 14-year-old Jesse Romero.

In all three cases, juries sided with the officers.

Times staff writer Maloy Moore contributed to this report.