IDAHO - A defense investigator working on behalf of University of Idaho student murders suspect Bryan Kohberger asserted in a newly unveiled court filing that a surviving housemate has "exculpatory" information that is "material and necessary" to the alleged killer's defense.
Kohberger, a former criminology Ph.D. candidate, is accused of entering an off-campus home on Nov. 13 around 4 a.m., after the occupants, all undergrad students at the school, had been out on a Friday night into early Saturday morning.
Police allege he fatally stabbed four of the six people inside, Madison Mogen and Kaylee Goncalves, both 21, along with Xana Kernodle and Ethan Chapin, both 20. The three women lived there with the two survivors, while Chapin, Kernodle's boyfriend, was spending the night.
Of the two survivors, one allegedly heard a commotion and witnessed a masked man exit through a rear sliding door, according to a police affidavit.
The second, a Nevada native named in the Nevada court filing made public Monday, allegedly heard or saw things that could clear the suspect, according to Richard Bitonti, a defense investigator working for Anne Taylor, Kohberger's court-appointed attorney.
In the documents, obtained by Fox News Digital, the subpoena demands the roommate's appearance on June 28, two days into Kohberger's planned preliminary hearing, and warns of a potential fine of $500 or 25 days in jail if she refuses to appear.
"During the course of my investigation, it became known to me that [she] has information material to the charges against Mr. Kohberger," Bitonti wrote in an affidavit in support of the subpoena, revealed Monday after online sleuths found the case listed on a Washoe County, Nevada, court docket.
A portion of that information, Bitonti added, "is exculpatory to the defendant."
The "information is unique to her experiences and cannot be provided by another witness," according to the documents.
As a result, Kohberger's defense is asking the court to compel her testimony at his scheduled preliminary hearing in June, as they hope to challenge the probable cause used to justify his arrest.
As Fox News Digital has reported, prosecutors can sidestep his attempts to disprove probable cause by seeking a grand jury indictment behind closed doors.
"If there is no preliminary hearing, because there was a superseding indictment, the issue of the subpoena (at least for that hearing) becomes moot," Edwina Elcox, a Boise-based criminal defense attorney who previously represented Lori Vallow, told Fox News Digital.
Even if a grand jury is empaneled behind closed doors, without involvement from Kohberger's defense team, prosecutors would be ethically bound to disclose potentially exculpatory evidence, she said.
However, a grand jury would enable prosecutors to present the case without subjecting any witnesses to harrowing cross-examination from Kohberger's defense before trial.
"The prosecutor has to present such exculpatory evidence to the grand jury, even though the defense is not present," she said.
The law firm representing the surviving roommate declined to comment, citing Idaho Magistrate Judge Megan Marshall's gag order on the case.
However, in a court filing opposing the subpoena, also published Monday, Reno-based attorney Kelli Anne Viloria argued that the Idaho subpoena was improperly filed and "there is no authority for an Idaho criminal defendant to summon a Nevada witness to Idaho for preliminary hearing."
"There is also no authority for an Idaho criminal defendant to summon a Nevada witness to an Idaho matter without a hearing and there is no authority to summon a Nevada witness to an Idaho matter without a Nevada judge making a finding of materiality, necessity and the lack of undue hardship," she added.
At the time of the stabbings, Kohberger was a Ph.D. criminology student at Washington State University, a neighboring school less than 10 miles away from the Idaho campus. He finished out the semester and drove home, cross-country, with his dad riding shotgun.
After his initial arrest, Kohberger's previous public defender in his home state of Pennsylvania said his client was looking forward to being exonerated.
Taylor, his attorney in Idaho, ignored requests for comment from Fox News Digital prior to the gag order and has since remained silent.
In court filings, her office has slammed what it calls "grotesquely twisted" media coverage of the home invasion stabbing that left four college students dead of multiple stab wounds each – some of whom were believed to have been sleeping at the start of the ambush.
Experts have told Fox News Digital that they expect Latah County prosecutor Bill Thompson to be extra careful as he seeks a conviction in the potential death penalty case in order to avoid possible grounds for appeal.
Last month, he informed Judge Marshall and Kohberger's team that his office would be disclosing this week "potential Brady/Giglio material" related to a police officer involved in the massacre probe – but that doesn't mean there is a connection with the stabbings of four University of Idaho students in November.
Brady material is information that could potentially prove a defendant's innocence, experts tell Fox News Digital. Giglio material is damaging to the integrity of a witness – in this case, one of the officers involved in the investigation.
In previously released court documents, investigators alleged they had linked the suspect to the crime scene through surveillance images of his car and phone records. They also found a knife sheath next to Mogen's body that allegedly contained DNA.
Kohberger faces four counts of first-degree murder and another of felony burglary. His preliminary hearing is scheduled to begin on June 26 and could take several days.