Boise man claimed to be delusional during stabbing. Court rules he can say that at trial
Idaho’s highest court ruled Wednesday that a Boise man who was off his medication and has a history of mental illness has the right to present evidence regarding his mental state at trial.
The state Supreme Court’s decision could set a legal precedent for future criminal cases. Justices ruled that even though Idaho abolished the insanity defense, state law “does not prevent a defendant from presenting relevant evidence of (their) mental state.” Idaho is one of four states — Montana, Kansas and Utah are the others — where there is no insanity defense.
In 2018, Ruben Diaz stabbed Gary Vinsonhaler, then 74, in the face, hand and neck, police and prosecutors have said. Diaz was charged with three felonies: aggravated battery, use of a deadly weapon in the commission of a crime and a persistent violator enhancement, according to online court records. He was also charged with misdemeanor resisting and obstructing an officer.
The gashes were so deep that Vinsonhaler suffered severe damage to facial nerves and major injuries to his hands from trying to fight off the blade, which resulted in permanent mobility damage.
“I looked up once and all I could see was red because my eyes had filled with blood,” Vinsonhaler testified during a 2019 court appearance.
Doctors diagnosed the 39-year-old Diaz with schizophrenia and autism sometime before 2008, according to records. He previously told the Idaho Pardons and Parole Commission that when he was not medicated, he could lapse into delusions that other people were aliens — a fact the commission was aware of when Diaz was placed into the custody of Hancock House, an unsecured group home, with orders to take his medication.
During the 2018 attack, Diaz believed Vinsonhaler “was not a person, but was instead an alien,” according to the Wednesday court opinion.
That argument was something prosecutors on the case did not agree with, causing the appeal to Idaho’s highest court as to whether it could be presented in court. The state had asked that expert testimony from Boise-area psychologist James Davidson be excluded.
Davidson found that “Mr. Diaz was delusional at the time of the offense and that, while Mr. Diaz admits slashing and cutting Mr. Vinsonhaler with a knife, Mr. Diaz, at the time he made the decision to do so, believed Mr. Vinsonhaler was not a person, but was instead an alien,” according to the Supreme Court opinion.
The prosecution argued that Davidson’s testimony was “irrelevant, prejudicial, and advanced a prohibited insanity defense.” Idaho’s Legislature banned the use of insanity as a defense in 1982.
The Idaho Supreme Court ruled that “expert testimony from Davidson on whether Diaz believed Vinsonhaler was human was relevant.” The court added that the “crux of the issue” is that “the State, for its part, must prove Diaz intended to attack a person — not an alien.”
Ada County Prosecutor’s Office spokesperson Emily Lowe told the Statesman by email that a new hearing date will be set by Ada County’s 4th District Court. Online court records have yet to be updated with that.
As of Wednesday, Diaz was in custody at the Ada County Jail on a $1 million bond, according to the online roster. Additionally, he is on a hold from the Idaho Department of Correction for prior assault offenses in 2007 and 2008.
This story was originally published April 6, 2022 at 4:23 PM.
