Idaho prosecutors have asked a judge to reject arguments from Bryan Kohberger's defense team against the possibility of the death penalty in his quadruple murder trial – and to shut down his request to have an outside expert testify on constitutional issues surrounding the quest for capital punishment.
Kohberger's defense, led by Anne Taylor and Elisa Massoth, made numerous requests outside the boundaries of established precedent, prosecutors wrote in a series of filings made public over the past week.
The 29-year-old's lawyers also argued that the state has "no viable method" to conduct executions and that there has not been enough time to adequately prepare the case against him.
"The thrust of Defendant’s argument is that the applicable aggravating factors in a capital case must be presented to a grand jury," wrote Special Assistant Attorney General Jeff Nye and Latah County Prosecuting Attorney Bill Thompson. "His argument is squarely foreclosed by binding Idaho Supreme Court precedent."
ACCUSED IDAHO COLLEGE KILLER BRYAN KOHBERGER'S TRIAL DATE PUSHED BACK
Bryan Kohberger, right, is escorted into a courtroom to appear at a hearing in Latah County District Court on Sept. 13, 2023 in Moscow, Idaho. (AP Photo/Ted S. Warren)
They wrote that they met their own legal obligations by including a probable cause affidavit in the superseding indictment and by notifying the defense that the state planned to seek the death penalty within 60 days of his arraignment, when a judge entered not guilty pleas to all charges on his behalf.
Under the law, they added, they were not required to include additional probable cause for each "aggravating circumstance" that led them to seek capital punishment.
They also rejected Kohberger's claim under the Eighth Amendment that the death penalty could be cruel or unusual punishment if prosecutors seek it without consulting a "neutral fact finder."
In a separate filing, Thompson also asked the judge to reject the defense request for expert testimony against the death penalty option.
Madison Mogen, top left, smiles on the shoulders of her best friend, Kaylee Goncalves, as they pose with Ethan Chapin, Xana Kernodle, and two other housemates in Goncalves' final Instagram post, shared the day before the four students were stabbed to death. (@kayleegoncalves/Instagram)
"It is now well-established in Idaho that ‘testimony containing conclusions of law by an expert witness is generally inadmissible,’" Thompson wrote in court filings, citing the ruling in Ybarra v. Bedke. "As the Idaho Supreme Court has explained, ‘when an expert witness offers a legal conclusion it invades the province of the court to determine the applicable law.’"
BRYAN KOHBERGER'S DEFENSE TEAM OPPOSES DEATH PENALTY
Last month, the defense attacked the possibility of the death penalty on numerous grounds, ranging from "contemporary standards of decency" to an alleged violation of international law.
They claimed Idaho's two legal methods of execution – lethal injection and firing squad – violate both the Eighth and 14th Amendments, and they asserted that the firing squad "was never constitutional."
Bryan Kohberger's defense attorneys Anne Taylor, left, Elissa Massoth, center, and Jay Logsdon arrive at the Latah County Courthouse in Moscow, Idaho, on June 27, 2023. (Derek Shook for Fox News Digital)
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After Idaho reinstated the firing squad last year, one of the nation's leading experts on capital punishment, Fordham Law School Professor Deborah Denno, told Fox News Digital the method is far more humane than lethal injections, which have been badly botched in recent years.
"The firing squad is the quickest, surest and most error-free and the only technique for which we have skilled and trained professionals," she said at the time.
In fact, she added, if death row inmates were given a choice, she said she believed most would ask for a bullet rather than an injection.
Police search a home in Moscow, Idaho on Monday, Nov. 14, 2022 where four University of Idaho students were killed over the weekend in a quadruple homicide. The victims are Ethan Chapin, 20, of Conway, Washington; Madison Mogen, 21, of Coeur d'Alene, Idaho; Xana Kernodle, 20, of Avondale, Idaho; and Kaylee GonCalves, 21, of Rathdrum, Idaho. (Derek Shook for Fox News Digital)
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Investigators said cellphone pings placed Kohberger near the house the day of the murders, and they tracked his car throughout the area. However, defense lawyers have argued that he was nowhere near the house where the killings happened and was instead driving around cold mountain roads in the dark, because he liked to "see the moon and stars."
Kohberger was studying at Washington State University in Pullman, Washington, at the time of the murders. The school is just a 10-mile drive across the state line from the crime scene, steps off campus at the University of Idaho in Moscow, Idaho.
Bryan Kohberger is now in the custody of the Ada County Sheriff's Office, according to online jail records. (Ada County Sheriff's Office)
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A 4 a.m. home invasion stabbing left four undergrads dead on Nov. 13, 2022 – Madison Mogen, 21, Kaylee Goncalves, 21, Xana Kernodle, 20, and Ethan Chapin, 20.
Police found a Ka-Bar knife sheath under Mogen's body that allegedly had Kohberger's DNA on the snap.
Kohberger faces four charges of first-degree murder and a count of felony burglary.
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A hearing on the death penalty issue was scheduled for Nov. 7.
Kohberger's defense successfully argued for a change of venue earlier this year, taking the case from Latah County, where he had been incarcerated since January 2023, to Ada County, where he is expected to go to trial next year.
Fox News' Audrey Conklin and Greg Wehner contributed to this report.