MINNEAPOLIS — The four former Minneapolis police officers charged in George Floyd's killing appear to be turning on one another, with each offering significantly different versions of the infamous arrest that acknowledge Floyd should not have been allowed to die that day but also deflect the blame to others.

The four men have said in court documents that they all thought someone else was in charge of the scene on May 25 — with rookie officers arguing they were deferring to a veteran, and the veteran saying he was simply assisting in an arrest that was in progress. All have said in court documents that the relationship between the veteran officer — Derek Chauvin — and the others is at the heart of the issue, as each officer perceived their role, and who was in charge, quite differently. Chauvin was the officer shown with his knee on Floyd’s neck as he struggled to breathe in videos of the ill-fated arrest.

“There are very likely going to be antagonistic defenses presented at the trial,” Earl Gray, a lawyer for Thomas K. Lane, wrote in a legal motion filed here this week. “It is plausible that all officers have a different version of what happened and officers place blame on one another.”

Gray and lawyers for Chauvin, J. Alexander Kueng and Tou Thao have been arguing to separate the former officers’ cases for purposes of trial, citing competing stories from their clients about the events that led to the 46-year-old Black man’s death. The officers are scheduled to appear in court Friday as a judge takes up that question; prosecutors have been asking for a joint trial.

Minneapolis authorities are locking down the area around the courthouse because of planned protests Friday. Windows on government buildings have been boarded up and law enforcement officials are setting up a perimeter to keep protesters at a distance.

Floyd died May 25 while handcuffed and restrained facedown on a South Minneapolis street as police investigated a 911 call about a counterfeit $20 bill that had been passed at Cup Foods, a local convenience store. During a struggle with police, Floyd was placed on the ground, where Chauvin pressed his knee into the man’s neck for almost eight minutes as Floyd repeatedly complained of struggling to breathe until he lost consciousness and no longer had a pulse.

Floyd’s death sparked a nationwide movement for social and racial justice, with protests emerging in cities from coast to coast along with a renewed and widespread push for police reform. Some of the protests have pitted social justice activists against those backing law enforcement officers.

While police often stand in solidarity during use-of-force investigations, Floyd’s case could be an unusual departure, with the officers who allegedly played a role in his killing arguing that other officers should be held to account instead.

Eric Nelson, Chauvin’s lawyer, said his client didn’t know the full picture of what was happening when he arrived on the scene at 38th Street and Chicago Avenue and saw Kueng and Lane struggling to get Floyd into a squad car.

Nelson, who has argued that Floyd died of a drug overdose and not from Chauvin’s knee restraint, blamed the rookie officers in a motion filed this week, suggesting they had mishandled the scene and caused Floyd’s death. He said the former officers delayed in requesting an ambulance when they suspected Floyd might be on drugs or was having a medical issue and that they did not do enough to try to calm Floyd down by “sitting him on the sidewalk” or “render aid instead of struggle.”

“If EMS had arrived just three minutes sooner, Mr. Floyd may have survived. If Kueng and Lane had chosen to de-escalate instead of struggle, Mr. Floyd may have survived,” Nelson wrote. “If Kueng and Lane had recognized the apparent signs of an opioid overdose and rendered aid, such as administering naloxone, Mr. Floyd may have survived.”

Chauvin has been charged with second-degree murder and manslaughter, while Kueng, Lane and Thao have been charged with aiding and abetting murder. All four were fired by the Minneapolis police department and are defendants, along with the city of Minneapolis, in a federal wrongful-death civil suit filed by Floyd’s family. Justice Department officials also are investigating and are said to be nearing a decision on possible federal charges in the case, according to sources familiar with the investigation, who spoke on the condition of anonymity because they were not authorized to speak publicly.

Chauvin is slated to make his first in-person court appearance at Friday’s hearing. Since his arrest May 29, he has attended all hearings remotely from a state prison where he is being held on a minimum $1 million bail. He is the only officer charged in the case who is still jailed.

Lawyers for Kueng and Lane, rookies who had been on the force for less than a week at the time of Floyd’s death, have argued that their clients were following orders from Chauvin, a 19-year-veteran of the department who had been Kueng’s field training officer and informally advised Lane during his probation period.

Lane, who was holding Floyd’s legs, twice asked Chauvin whether they should reposition Floyd — requests that his lawyer says prove that he tried to intervene with a senior officer but was rebuffed. After Floyd appeared to have stopped moving, Lane told Chauvin he was worried about “excited delirium,” citing a term used by medical examiners to describe the sudden in-custody death of people who might be under the influence of drugs or who are in an agitated state.

“That’s why we got the ambulance coming,” Chauvin told him.

“Okay, I suppose,” Lane replied.

Lawyers for all four former officers have suggested in recent court filings that they plan to argue that Floyd’s death was accelerated by drugs in his system — including what the Hennepin County medical examiner told prosecutors in June was a potentially lethal amount of fentanyl, according to recently disclosed interview notes filed as evidence in the case.

Kueng’s lawyer, Thomas Plunkett, wrote in a court filing this week that his client, who was restraining Floyd’s back, was only on his third shift as a police officer that day and that he had spent approximately 420 of his 730 hours of field training “being taught and evaluated by Chauvin,” whom he was required to call “sir.”

Plunkett suggested he plans to introduce evidence of how Chauvin trained Kueng — including “past opinions and directions” and “past statements he has made about how to handle a subject being detained,” which he wrote would be “derogatory” to Chauvin’s defense.

“Kueng will shift blame onto Chauvin during trial,” Plunkett wrote.

Chauvin, who has largely been silent most of the summer, is trying to recast his role at scene in recent days, aiming to shift the blame back on Kueng and Lane.

Chauvin and Thao, who were partners that day, have argued through their lawyers that they responded to provide backup to the other officers, who first encountered Floyd as he sat in a parked SUV. Lawyers for Chauvin and Thao have described their clients as supporting officers who were deferring to Kueng and Lane on how to handle Floyd and that seniority and rank didn’t matter.

Lawyers for Thao and Kueng have indicated they will introduce evidence of Chauvin’s history as a Minneapolis police officer. Last month, Thao’s lawyer, Robert Paule, filed a motion demanding the state disclose the “complete Minneapolis Police Department disciplinary files” for Chauvin — records the police department thus far has declined to release in detail, aside from records showing he was the subject of 18 complaints, 16 of which were dismissed.

Thao has sought to have his charges dismissed, shifting blame to Chauvin, Kueng and Lane, who had more direct contact with Floyd. In a May interview with investigators with the Minnesota Bureau of Criminal Apprehension and the FBI, which was filed as evidence in the criminal case, Thao described his role at the scene as “a human traffic cone.” He said he was focused on controlling a growing number of bystanders and was unaware of what was happening behind him.

Thao told investigators that he and Chauvin had been called as backup to the scene, but they were canceled by dispatch. Thao said he decided that they should continue to Cup Foods anyway because Kueng and Lane were “so new” and the area was known to be hostile to police.

Police body-camera footage shows that Thao advised the other officers to put Floyd on the street after they tried and failed to get him inside a squad car.

“Just lay him on the ground,” Thao tells the other three officers, who comply.

Though Thao looks for a hobble — a leg restraint that would keep Floyd immobile and allow the officers to lift their bodies off his — he and the officers ultimately decide to skip the device and wait for the ambulance, believing the hobble would be more hassle than it was worth. But the ambulance, requested without lights or sirens, was delayed by several minutes.

In his interview with investigators, Thao echoed Chauvin’s argument, that he believed that Kueng and Lane were in charge of the scene because they were the first to arrive.

“This is 320’s call,” Thao said, referring to the squad car number Kueng and Lane were driving that day.

Prosecutors have filed an objection to Thao’s motion to dismiss charges, arguing that all officers have a responsibility to stop another officer from committing a crime. They dispute his claim that he was unaware of what was happening around him, citing body-camera footage that shows him shoving and screaming at bystanders — including an off-duty Minneapolis firefighter — who urged officers to check Floyd for a pulse and that he ignored Floyd’s “desperate cries.”

Judge Peter A. Cahill, who is presiding over the criminal case, has said he will hear arguments Friday on the issue of joint or separate trial, proceedings he has scheduled to begin in March. He also is slated to take up motions to dismiss and move the trial out of Hennepin County, where defense lawyers say it is impossible to impanel a fair jury.