DENVER (AP) – A Colorado man accused of killing his wife after eating marijuana-infused candy he bought at a legal pot shop was experiencing psychotic-like symptoms due to the drug, a doctor wrote in recently filed court documents.

Richard Kirk, 49, faces first-degree murder charges in the April 2014 shooting death of his wife, Kristine, who died while describing his erratic behavior on a 911 call. His attorneys have suggested that Kirk was so impaired by the candy that he may not have intended to kill her.

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He changed his plea Friday to not guilty by reason of insanity, and the court documents give new details about his defense.

Kirk was intoxicated with THC, marijuana’s psychoactive ingredient, which led to delirium, Dr. Andrew Monte, a defense witness, wrote in his report that was submitted to the court in August.

A spokeswoman for the Denver district attorney’s office declined to comment on the doctor’s opinion.

Just before she was shot, Kristine Kirk told dispatchers that her husband was acting more drunk than violent, crawling through a bedroom window and cutting his legs on broken glass. But prosecutors argue he had the wherewithal to remember the code to a gun safe and press the weapon to his wife’s head. They have said the couple had been fighting over marital and financial problems.

The shooting stoked concerns about the effects of the marijuana snacks, which have become popular since the state legalized recreational marijuana. Colorado lawmakers last year tightened regulations on edible marijuana, responding to the Kirk case and the death of a college student who jumped from a hotel balcony after eating a potent marijuana cookie.

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It is still unclear what role marijuana could play in Kirk’s defense. Willful drug and alcohol use cannot be the basis for an insanity defense in Colorado. For Kirk to be found legally insane, experts say, his attorneys will have to prove he suffered from a mental illness separate from his marijuana use that rendered him unable to tell right from wrong.

A different doctor who examined Kirk at the request of his defense attorneys found a number of problems, including “paranoid inclinations.”

“He is prone to unraveling both cognitively and emotionally when under stress, and symptoms are likely to include features of paranoia, significant distortions in thinking and unrestrained affect,” clinical psychologist Katherine Bellon wrote in her report.

As a result of his insanity plea, Kirk will be evaluated at the Colorado Mental Health Institute in Pueblo before a December hearing.

– By Sadie Gurman, AP Writer

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