HAGERSTOWN, Md. - Roger Largent will never get a chance to clear his name in the rape of a disabled woman: He was found beaten to death in his prison cell four days before a court tossed his conviction.

Authorities suspect Largent's cellmate in the slaying, but they have not cited a motive or filed charges in the Saturday attack.

On Wednesday, a Maryland appeals court threw out Largent's conviction and said he should get a new trial because the jury verdict last year hinged largely on a prosecution witness' improper testimony.

The assault happened in 2015 when Largent went to the mentally disabled woman's house to give her and her blind husband a ride to a doctor's appointment. The woman testified at trial that Largent walked up behind her, covered her mouth, pulled down her pants and raped her in the kitchen while her husband was upstairs.

"If I screamed or said anything, he would kill me," the woman testified, according The Herald-Mail newspaper.

The woman told her husband what happened later that night, and Largent was questioned by police.

In a videotaped interview with police, Largent initially denied having sex with the woman, a family member in her late 40s. When a detective told Largent that his DNA was found on the woman, Largent said it was consensual sex and that "she came on to me first."

The officer later acknowledged that his statement during the interrogation about DNA was not true. The Supreme Court has given police leeway to lie to suspects during questioning.

At trial, assistant public defender Amy Taylor suggested that the woman made the rape allegation because she felt guilty about being unfaithful. Taylor noted that the accuser did not have any bruises or scratches.

That made the testimony of the nurse who examined the woman, Ashley Hall, crucial to the case. Hall testified that a woman can be raped but show no bruising or other physical signs of an assault.

Although Hall was trained in the examination of sexual assault victims, prosecutors did not seek to qualify her as an expert despite defence objections that her testimony would amount to an expert opinion. Deputy Washington County State's Attorney Gina Cirincion said Thursday that she did not ask the court to qualify Hall as an expert because the nurse had little trial experience and had only recently completed her training.

Largent's lawyers said Hall's testimony provided "critical guidance as to the only contested point at trial" - whether the intercourse was consensual. The appellate court agreed.

The trial court "abused its discretion in permitting Ms. Hall to offer a lay opinion," the ruling said. Hall "relied on scientific and medical training beyond the understanding of the average juror when offering her testimony."

The state asked the appeals court Thursday to recall its opinion in light of Largent's death.

The public defender's office asked the court to delay the proceedings so his family or estate could appoint someone to make legal decisions.

Taylor said Largent's death was a shock, making the appellate victory bittersweet.

"I thought it had a good chance of being reversed," she said. "We were right, and he was going to get this fair trial and now he's been deprived of that opportunity."

Cirincion, the prosecutor, said the state would have retried and convicted Largent again if he were alive.

"Roger Largent was where he belonged at the time of his death," she said.

Largent, 69, was serving time at the maximum-security Western Correctional Institution when his body was found. Authorities have not released many details, except to say they suspect his cellmate. No charges have been filed.

In 1999, Largent was convicted of a third-degree sex offence against a juvenile female family member and had to register as a sex offender.