PARK CITY, Utah — A Utah judge has issued a series of closely watched rulings on expert testimony in the murder case against author Kouri Richins, narrowing what jurors will hear when the case goes to trial and underscoring the court’s role as gatekeeper over specialized evidence.
Eric Richins died in March 2022. An autopsy later revealed he had ingested fentanyl at a level multiple times higher than what is considered fatal. Prosecutors allege his wife administered the drug in a Moscow mule cocktail. They also claim she previously attempted to poison him using medication weeks earlier.
Kouri Richins was arrested in May 2023 following a lengthy investigation. In addition to the murder charge, she faces counts related to insurance fraud and forgery. She has pleaded not guilty and has maintained her innocence.
Richins, whose children’s book about grief gained national attention after her husband’s death, is charged with aggravated murder and multiple additional counts related to the 2022 poisoning death of her husband, Eric Richins. Prosecutors allege she secretly administered a fatal dose of fentanyl in a cocktail at the couple’s home and had previously attempted to poison him weeks earlier.
At a recent pretrial hearing, Third District Judge Richard Mrazik ruled on several defense motions seeking to exclude expert witnesses proposed by the state. His decisions will significantly shape how prosecutors are allowed to frame motive, behavior, and forensic interpretation for jurors.
Behavioral Expert Largely Barred
One of the most contested rulings involved a prosecution expert who was expected to testify about a so-called “pathway to violence” model — a theory used in some academic and law-enforcement circles to describe patterns that may precede targeted acts of violence.
Defense attorneys argued the model lacks sufficient scientific grounding and risks inviting jurors to infer guilt based on generalized behavioral profiles rather than evidence specific to Richins. Judge Mrazik largely agreed.
In his ruling, the judge prohibited the expert from applying the pathway-to-violence theory directly to Richins or using it to suggest culpability. However, he left open a narrow possibility for the witness to testify later in the trial as a “blind expert,” meaning the testimony could be limited to general principles and only if the defense introduces certain arguments that make such context relevant.
The decision reflects growing judicial caution nationwide about behavioral profiling testimony that may blur the line between education and speculation.
Handwriting Expert Allowed to Testify
The judge reached a different conclusion regarding a handwriting analysis expert the prosecution intends to call. The defense sought to exclude the testimony, arguing that handwriting comparison methods are unreliable and could mislead jurors.
Judge Mrazik denied the motion, allowing the expert to testify under standard evidentiary constraints. The expert is expected to address disputed documents connected to the case, including records prosecutors allege were altered or forged.
While acknowledging the defense’s concerns, the judge ruled that the testimony meets the threshold for admissibility and that challenges to methodology can be addressed through cross-examination rather than exclusion.
Domestic Abuse Expert Excluded — For Now
A third ruling temporarily removed another proposed prosecution expert from the witness list. Prosecutors had planned to call a psychologist specializing in domestic abuse dynamics, arguing the testimony could help jurors understand the relationship between Richins and her husband.
Judge Mrazik sided with the defense, stating that the court had not yet seen sufficient evidence of a history of domestic abuse to justify introducing such expert testimony. As a result, the expert will not be permitted to testify at this stage.
However, the judge emphasized that the ruling is conditional. If prosecutors later establish that Eric Richins had reason to fear his wife or believed she intended to harm him — particularly in connection with the alleged earlier poisoning attempt — the court may reconsider allowing the testimony.
Why Expert Testimony Matters in This Case
The Richins case is heavily dependent on expert interpretation. Prosecutors allege Eric Richins died after ingesting fentanyl at levels far exceeding a lethal dose. Because there were no witnesses to the alleged poisoning, the state’s case relies on forensic toxicology, digital evidence, financial records, and expert explanations of behavior and motive.
Defense attorneys have argued that expert testimony must be tightly controlled to prevent jurors from being swayed by theories or conclusions not firmly rooted in evidence.
Judge Mrazik’s rulings reflect that tension. By allowing technical testimony in some areas while restricting broader behavioral interpretations, the court has drawn clear lines around what experts may and may not do at trial.
Eddie Price
https://witnessdirectory.com/USAexpertwitnesses/non-medical-experts/handwriting-analyst/
https://witnessdirectory.com/signup.php
