By Holly Yan and Jamie Gumbrecht

(CNN) — Attorneys for the man accused of stabbing four University of Idaho students to death have nodded to autism spectrum disorder in asking the court to ensure the 30-year-old wouldn’t get the death penalty if convicted, court records show.

Bryan Kohberger is accused of killing Madison Mogen, Kaylee Goncalves, Xana Kernodle and Ethan Chapin at an off-campus home in November 2022. Kohberger’s trial is expected to begin in August; not guilty pleas have been entered on his behalf.

The slayings shrouded a college town in grief and fear as authorities embarked on a cross-country search that culminated with the arrest of Kohberger, a criminology graduate student, in Pennsylvania more than a month after the killings.

His defense recently filed a motion “to Strike Death Penalty RE: Autism Spectrum Disorder,” summaries of court documents show. A “Motion to Redact or Seal Newly Filed Records” was also entered “in Support of their Motion to Strike Death Penalty RE: Autism Spectrum Disorder Under Seal.”

As of early Wednesday morning, the full documents were not publicly available online. And it was not immediately clear whether Kohberger has been diagnosed with autism spectrum disorder or if the defense was seeking a diagnosis.

The motions mark the latest attempt by Kohberger’s attorneys to try to remove the possibility of the death penalty.

The efforts also follow their failed attempt to convince a judge to suppress evidence related to investigative genetic geneaology, a relatively new technique in which authorities upload an unknown suspect’s DNA profile to a database to learn about potential relatives.

The prosecution, meanwhile, recently asked the judge to bar the use of an alibi defense and the claim there was another perpetrator without evidence being shared first. Prosecutors also asked for some sealed expert testimony on Kohberger’s mental health to not be allowed.

Limited research about autism and crime

Autism spectrum disorder is a neurological and developmental disorder that can affect how people interact with others, communicate, learn and behave, according to the National Institute of Mental Health.

While research about people with autism or autism-like characteristics and crime is limited, studies have suggested they’re no more likely than people without autism to offend or encounter the criminal justice system.

Advocacy groups Autism Speaks and the Autism Society have pushed for more training among law enforcement and the judicial system to recognize people’s diagnoses, characteristics and needs.

“A diagnosis of an autism spectrum disorder is as relevant to police and legal proceedings as a diagnosis of mental retardation or mental illness would be, no matter how bright, high functioning, and/or verbal the person may be,” Autism Speaks said in a resource page on the judicial system.

“An individual’s Autism diagnosis must be considered when determining appropriate sentences and rehabilitation programs,” the Autism Society said.

Several attempts to avoid the death penalty

Kohberger’s lawyers filed a spate of motions last year listing a variety of reasons they believe the state’s intent to seek the death penalty is unconstitutional.

One motion focuses on what Kohberger’s defense team calls an “ideological shift” and “evolving standards” in the way Americans view the death penalty.

“The lack of an active death penalty in the majority of states within the United States indicates that there has been an ideological shift and that the punishment now violates our contemporary standards of decency,” they wrote, noting five US states have abolished the practice in recent years.

Other motions argue Idaho’s death penalty statute constitutes a violation of international law and the fundamental precepts of international human rights. They also argue Idaho’s methods of execution – lethal injection and firing squad – are cruel and unusual punishment and therefore violate the US Constitution.

Prosecutors, meanwhile, last week cited a state law providing “mental condition shall not be a defense to any charge of criminal conduct” except “expert evidence on the issues of any state of mind which is an element of the offense,” a court filing shows.

This story has been updated with additional information.

CNN’s Taylor Romine, Veronica Miracle, Kevin Flower, Cheri Mossburg and Elizabeth Hartfield contributed to this report.

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