DENVER (CBS4) – Richard Kirk, 48, has changed his plea to not guilty by reason of insanity in the death of his wife.

The shooting happened on April 14, 2014 at their home in Denver’s Observatory Park. Kristine Kirk, 44, was killed while on the phone with 911 asking for assistance. A dispatch went out over the police radio.

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“St. Paul Street report domestic violence in progress. RP verses her husband has been smoking marijuana. Advises they do keep a hand gun in the house but is not in anybody’s possession,” the dispatch said.

Kristine Kirk told the 911 call taker her husband was hallucinating after eating marijuana candy and asked her to kill him. She was the one who ended up dead after her husband unlocked a gun from a safe.

The police dispatcher said, “332 Adam go ahead, yeah, according to the notes he grabbed the gun and she screamed and the line disconnected. Can we step up cover?”

Kristine Kirk and Richard Kirk (credit CBS)

Kristine Kirk and Richard Kirk (credit CBS)

CBS4 Legal Analyst Karen Steinhauser says the insanity plea goes beyond just using pot edibles.

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“If this was just about marijuana I don’t think we would be seeing an insanity defense,” Steinhauser said.

She says there has to be some mental disease so that Kirk did not know difference between right and wrong.

Police determined the couple had been arguing prior to that day with the husband moving his paycheck deposits into his own account. But now the defense will argue he was insane when he shot his wife to death.

“Other than marijuana edible that the delusion could have caused him to do the actions that he did,” Steinhauser said.

Kirk will now be sent to the Colorado State Hospital in Pueblo for a psychiatric examination. His trial was scheduled for October. He is now due back in court Dec. 17.

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CBS4’s Rick Sallinger is a Peabody award winning reporter who has been with the station more than two decades doing hard news and investigative reporting. Follow him on Twitter @ricksallinger.