MINNEAPOLIS, United States (AP) — Attorneys for three former Minneapolis officers awaiting trial in George Floyd’s death will be in court Thursday to argue pretrial motions, including a request that prosecutors be sanctioned after media reports that Derek Chauvin had planned to plead guilty a year ago, and allegations that they haven’t disclosed information about the alleged coercion of a witness.

Attorneys for Thomas Lane, J Kueng and Tou Thao have said they want the court to require prosecuting attorneys to submit affidavits under oath that they aren’t responsible for the leak to the media. In a filing late Wednesday, Thao’s attorney also alleged that the Hennepin County medical examiner was coerced to include “neck compression” in his findings — and that prosecutors knew of it.

The former officers waived their right to appear at Thursday’s hearing. Their trial is set for Aug. 23.

Attorney General Keith Ellison, whose office is prosecuting the officers, has said allegations that his office was involved in a leak are false. His office had no immediate comment on the allegations of coercion. A spokeswoman for Dr Andrew Baker, the medical examiner, said they could not comment due to the pending case.

Chauvin, who was seen in widely viewed bystander video pressing his knee into Floyd’s neck as the Black man said he couldn’t breathe, was convicted in April of second-degree unintentional murder, third-degree murder and manslaughter. He’s to be sentenced June 25.

Lane, Kueng and Thao are charged with aiding and abetting second-degree murder and aiding and abetting second-degree manslaughter. Their trial was separated from Chauvin’s to comply with COVID-19 courtroom spacing restrictions.

Bob Paule, Thao’s attorney, said in a court filing Wednesday that Baker initially said there was no physical evidence that Floyd died of asphyxiation. But after talking twice to Dr Roger Mitchell — a former medical examiner in Washington, DC — he amended his findings to include neck compression as a factor, according to Paule.

Paule said that in one of the conversations, Mitchell called Baker and told him he was going to submit an opinion piece critical of Baker’s findings to the Washington Post. When Baker released final autopsy findings June 1, they included neck compression, Paule wrote, and Mitchell never submitted his piece to the newspaper.

Mitchell, now chairman of the Department of Pathology at the Howard University College of Medicine, did not immediately respond to a phone message left at the department after hours.

Paule also took aim at Mitchell’s criticism of Dr David Fowler, a key defence witness for Chauvin who testified that the former officer was not responsible for Floyd’s death. Mitchell sent a letter — signed by 431 doctors from around the country — to the Maryland attorney general, saying Fowler’s conclusions were so far outside the bounds of accepted forensic practice that all his previous work could be questioned.

Maryland officials then announced they would review all in-custody death reports during Fowler’s tenure. Paule said Mitchell’s accusations had a chilling effect on Thao’s ability to find medical experts unafraid to testify on his behalf.

He said prosecutors have yet to give the defence evidence about Mitchell’s actions. He’s asking that the case against Thao be dismissed.

Paule also said in a court filing in February that he wants an order sanctioning the state for “its role — directly or indirectly — in the leaking of highly prejudicial information related to potential plea agreements of co-defendants.”

The New York Times reported Feb. 10 that Chauvin was ready to plead guilty to a third-degree murder charge last year but then-Attorney General William Barr rejected the agreement. The Associated Press published a similar report the next day, citing two law enforcement officials with direct knowledge of the talks. Paule alleged that the leaks came from the state, and asked that anyone who did so be barred from participating in the trial. Tom Plunkett, Kueng’s attorney, echoed his statements.

Ellison earlier dismissed Paule’s motion as “completely false and an outlandish attempt to disparage the prosecution”.

Earl Gray, Lane’s attorney, has a motion asking Judge Peter Cahill to compel the state to disclose all use-of-force reports over the past 50 years in which a Minneapolis police officer used force and another officer intervened verbally or physically. Gray said it’s necessary to show the jury that no such intervention has been made in the past 50 years, which would call into question the state’s expert testimony about the duty of officers to intervene.

Prosecutors have said that request should be denied. They’ve noted that department policy requires officers to intervene when excessive force is used, and say Gray hasn’t shown how the testimony of experts could be called into question by a lack of interventions.

All four officers have also been indicted on federal charges alleging they violated Floyd’s civil rights.