Back then, an H.I.V. diagnosis meant debilitating symptoms and almost certain death.

For the last five years, Steven Thrasher, a journalism professor at Northwestern University, has chronicled Michael L. Johnson’s case for BuzzFeed News and recently completed his doctoral dissertation on race and H.I.V. criminalization.

Dr. Thrasher, who greeted Mr. Johnson outside the correctional facility on Tuesday, said he was first drawn to the case because of its parallels with the history of black sexuality and lynching.

“Black men would just get lynched anytime they had sex with white women in the Reconstruction period,” he said. “There was no consensual sex that could be had between white women and black men.”

Mr. Johnson’s wrestler’s body — he called himself “Tiger Mandingo” online — was a source of fascination for some of his partners. But when Mr. Johnson tested positive for H.I.V., Dr. Thrasher wrote, he became “the perfect scapegoat.”

“It was not that he had no agency or responsibility in the story,” Dr. Thrasher said on Thursday, but “he was really holding all of this anxiety and all of this worry about AIDS and stigma and H.I.V. and queerness in America all on his shoulders.”

Mr. Lohmar, the St. Charles County prosecutor, said on Thursday that “nothing about the trial was unfair,” except for his team’s failure to present certain evidence to the defense in time.

Because prosecutors did not disclose some evidence to the defense until the morning of the trial — recorded phone conversations Mr. Johnson made while in the county jail — an appeals court decided to overturn the conviction 17 months after the original sentencing.