Prosecutors will not be able to use statements made by a man accused of sexual assault because he did not knowingly and intelligently waive his constitutional rights before talking to a Casper Police detective, a judge ruled Monday.

Natrona County District Court Judge Catherine Wilking agreed with Levi Zitterkopf's defense attorneys that he did not understand what was happening during an interview last year with a detective and that prosecutors could not show he did understand.

"The state has not met its burden of proof," Wilking said.

She made her ruling after hearing an audio recording with the detective, Zitterkopf and a probation officer, and she said statements in the recording contradicted what the detective said in court.

Zitterkopf, who was featured on the History Channel show "Ax Men," is charged with a single count of first-degree sexual assault. If convicted, he could face five to 50 years in prison and a $10,000 fine.

The case began in August 2016, when the victim told investigators she and her family moved into a home the previous week and she met Zitterkopf who eventually sexually assaulted her.

Zitterkopf's trial is scheduled to begin next week. He is free on $25,000 bond.

In March, his attorney entered pleas of not guilty and not guilty by reason of mental deficiency on his behalf during his arraignment.

During the motion hearing Monday morning, public defender Patrick Lewellan interviewed psychologist Mark Watt by a telephone conference call. Watt examined Zitterkopf, who was in special education classes throughout his school years, dropped out in the 11th grade, and has a learning disability

Zitterkopf can read but not necessarily comprehend what he read, Watt said.

Detective Jonathan Peterson testified, and told Assistant District Attorney Kevin Taheri about his interview of Zitterkopf at the county jail on Sept. 8, 2016.

A portion of the recorded interview was played during the hearing.

Peterson gave Zitterkopf a copy of the Miranda warnings about the right to not self-incriminate, and by signing the warning Zitterkopf would waive his right to an attorney.

Part of that process involves an officer making sure a defendant understands he is waiving his rights without any threats, promises, or coercion.

Peterson asked Zitterkopf if he knew what "coercion" meant, and Zitterkopf responded that it means pressure.

In his closing argument, Taheri said the only word Zitterkopf asked about was "coercion"; and Peterson twice asked him if he questions about what he read.

However, Lewallen said the issue isn't whether Zitterkopf was coerced into signing the waiver.

Rather, the questions are whether Zitterkopf knowingly and intelligently signed the waiver, which are requirements of court interpretations of the Fifth Amendment, Lewallen said. "The question is whether he understood it."

Wilking said at the end of that hearing that she needed to listen to the entire audio recording to understand the context.

After reconvening the hearing Monday afternoon, she said a defendant who waives their rights must understand the nature of the rights and the consequences of waiving those rights.

Peterson told the court he asked Zitterkopf twice if he understood the questions, but the recording did not bear that out, Wilking said.

During the interview, Zitterkopf several times asked Peterson what certain things meant, but Peterson never gave answers, she said.

The interview was deficient in that it did not ask about Zitterkopf's employment history, prior encounters with law enforcement or the criminal justice system, Wilking said.

Peterson and the probation officer also had a long discussion about whether Zitterkopf was on probation, but nothing was clarified.

At certain times, the defendant would use legal terms but he did not understand their meaning, Willking added.

When taken together, Zitterkopf did not understand what was happening and the interview with Peterson will not be allowed, she said. "The defendant's statement is suppressed."