Mr. Cameron’s mother, Monica Lee, described her son as an outgoing young man who could quickly turn strangers into friends with his smile. Ms. Lee has always maintained that the deputies killed her son by violently subduing him and ignoring his cries that he could not breathe. She predicted the investigation into his death “was going to be a bunch of lies.”

Ms. Lee sued the department in 2022.

Her lawyer, Malik Shabazz, said the conclusions of the independent pathologists could change the outcome of Ms. Lee’s case. “There’s serious questions about the competency and the accuracy of the autopsy findings,” he said.

Mr. Cameron is one of at least nine men who have died during episodes involving Rankin deputies since 2014, according to department records and Mississippi Bureau of Investigation reports.

Rankin County, a rural, majority-white community outside Jackson, has been rocked by national controversy this year after five sheriff’s deputies and a local police officer broke into the home of two Black men, tortured them for two hours, sexually assaulted them with a sex toy and then shot one of them in the mouth. All of the officers have pleaded guilty to federal and state charges.