A man convicted in Jefferson County for sexual assault will receive a new trial after the state’s Court of Appeals determined his jury heard improper testimony from an expert witness.

Prosecutors called an expert in sex assault, trauma and behavior dynamics to testify at the 2018 trial of Alfonso McGregor. The prosecutor asked the expert how common it is for women to falsely report a rape.

“False reporting is very uncommon,” she responded. “So, there’s a lot of research that looks at this. It depends on the research study you look at, but, you know, false reporting is a much smaller problem when you look at their statistics.”

McGregor appealed his conviction, claiming the expert’s testimony inappropriately vouched for the alleged victim’s credibility. A three-judge panel for the Court of Appeals agreed on Thursday, finding that even though McGregor did not object at trial, it was well settled that a witness may not testify that another witness is telling the truth.

“Equally well settled is that testimony regarding the infrequency of false reporting runs afoul of this prohibition,” wrote Judge Ted C. Tow III.

The Court of Appeals has also reversed convictions in similar cases based on testimony that sex abuse allegations have been “screened” prior to prosecution, implying that only truthful claims had moved forward.

The case is People v. McGregor.