A Kansas sheriff’s deputy who is charged with murdering a handcuffed jail inmate held his knee against the prone man’s back for 1 minute 26 seconds, court records say.

Richard Fatherley, a deputy sheriff in Wyandotte County, Kan., was charged in September with second-degree murder or an alternative of involuntary manslaughter in connection with the death of Charles Adair on July 5 at the county jail in Kansas City, Kan.

Mr. Adair, who had several medical conditions and was using a wheelchair, had been arrested the day before based on misdemeanor warrants concerning traffic tickets, according to an affidavit filed in the case. The affidavit was released last week at the request of news organizations.

When he was arrested, Mr. Adair was taken to a medical center because of an infected wound on his left leg and then was cleared for incarceration and transported to the jail. Records cited in the affidavit said complications with the leg wound stemmed from untreated diabetes. Mr. Adair said during the medical screening that he had a pacemaker and was schizophrenic, the affidavit said.

At the jail on the evening of July 5, Mr. Adair was being wheeled back to his cell after getting the dressing on his leg re-wrapped when he got into a fight with the deputy and threw himself out of his wheelchair, according to the affidavit. He was handcuffed, put back in the chair and wheeled to his cell, where deputies placed him on the bottom bunk, lying face down.

He was heard yelling “help,” the affidavit said, and at 8:36 p.m., Mr. Fatherley approached Mr. Adair and put his left knee on Mr. Adair’s lower back, while other deputies held down Mr. Adair’s arm, shoulder and legs.

“You’re done, stop, give me your hands,” Mr. Fatherley told Mr. Adair, the affidavit said.

“OK,” Mr. Adair responded.

When Mr. Adair stopped moving, Mr. Fatherley appeared to shift forward and apply more weight onto Mr. Adair, the affidavit said, and continued to hold Mr. Adair down as the handcuffs were removed. Mr. Adair remained still, facing down on the bunk with his hands pushed forward, the affidavit said.

Mr. Fatherley took his weight off Mr. Adair’s back at 8:37 and left the cell, according to the affidavit. Mr. Adair was pronounced dead at 9:19 p.m.

An autopsy identified the cause of death as “complications of mechanical asphyxia” and his manner of death as “homicide.” Two contributory causes of death — “hypertensive cardiovascular disease and hepatic cirrhosis due to chronic alcoholism”— were listed.

Ben Crump, a lawyer representing the Adair family, said in a statement on Friday that the newly released court records confirmed that Mr. Adair “posed no threat when a deputy pressed a knee into his back, resulting in his death.”

Mr. Adair’s family has requested that video footage of the incident be released.

Mr. Fatherley’s lawyer, James Spies, said in a statement that Mr. Adair’s death was “not the result of excessive force” and pointed to Mr. Adair’s poor health.

“Mr. Adair’s death, while tragic, was an accident,” he said.

Mr. Fatherley has not been arrested. He is expected to appear in court in November.