The Idaho Supreme Court recently vacated the conviction of Michael James Hinkel for attempted strangulation, ruling that the trial court improperly admitted testimony from police officers who were not disclosed as expert witnesses. This decision, filed on May 18, 2026, affects Hinkel, who was found guilty in a lower court, and sets important precedents regarding the admissibility of witness testimony in criminal cases.

Hinkel's case began when he was accused of assaulting his then-girlfriend during an argument. The incident escalated to physical violence, with Hinkel allegedly striking the victim and attempting to strangle her. The victim reported the incident to the police, leading to Hinkel's arrest and subsequent trial. The case was brought to the Idaho Supreme Court after Hinkel appealed his conviction, arguing that the trial court erred in allowing certain testimonies.

The dispute centers on whether the testimony provided by the police officers at Hinkel's trial constituted expert testimony, which would require prior disclosure according to Idaho law. Hinkel contended that the officers' interpretations of the marks on the victim's neck were based on specialized knowledge, thus qualifying them as expert witnesses. The State, on the other hand, argued that the officers were merely providing lay opinions based on their observations.

During the trial, the officers testified that they observed red marks on the victim's neck, which they interpreted as signs of attempted strangulation. Hinkel objected to this testimony, claiming it was expert testimony that had not been properly disclosed. The trial court allowed the officers to testify, leading to Hinkel's conviction by a jury.

In its ruling, the Idaho Supreme Court found that the trial court had indeed erred in admitting the officers' testimony. The court stated, "We hold that the district court erred in admitting portions of the officers’ testimony" and emphasized that the officers' conclusions were based on their training and experience, which aligned with the definition of expert testimony under Idaho law.

The court's opinion highlighted that the officers' interpretations of the victim's injuries were not merely observations but were informed by their specialized training in domestic violence and strangulation cases. This meant their testimony required proper disclosure as expert witnesses, which had not occurred. The court concluded, "Because the officers testified as expert witnesses, we conclude that permitting them to testify without full disclosure as such was an abuse of discretion."

Furthermore, the court determined that the error was not harmless. The prosecution had relied heavily on the officers' testimony during the trial, and the court could not say that the error did not contribute to the jury's verdict. The Idaho Supreme Court vacated Hinkel's conviction and remanded the case for a new trial, stating that the lower court's error had a significant impact on the outcome.

This ruling has implications for future cases involving witness testimony in Idaho. It reinforces the importance of disclosing expert witnesses and adhering to legal standards regarding the admissibility of testimony. The decision may affect not only Hinkel but also other defendants in similar situations where the qualifications of witnesses come into question.

Going forward, Hinkel's case will return to the lower court for a new trial, where the admissibility of evidence will be scrutinized more closely. The prosecution may need to adjust its approach to ensure that any expert testimony is properly disclosed and that the trial adheres to legal standards. This case serves as a reminder of the critical role that proper legal procedures play in ensuring fair trials and just outcomes.

Details were not available in the court filing regarding whether the case could be appealed further or if there are related cases pending. However, the ruling sets a clear precedent for the treatment of witness testimony in Idaho courts.