Before shooting his wife to death, Richard Kirk asked her to kill him.

After the Denver father of three allegedly murdered her, he asked their 7-year-old son to do it, saying it would allow “Mom and Dad to be together with God.”

The fatal shooting came at the end of a 12-minute phone call between Kristine Kirk and police, one in which she told a dispatcher that her husband of 15 years was “totally hallucinating.” Hours earlier, the 49-year-old man had consumed half a small marijuana edible called “Karma Kandy Orange Ginger,” which he purchased at Nutritional Elements, a dispensary nearby.

In the two years since the April 2014 shooting, Kirk has pled not guilty by reason of insanity after saying the marijuana candy made him psychotic. Surprisingly, his wife’s family agrees with her alleged killer and is suing edible’s seller and maker for failing to put adequate warnings on the candy. Both Kirk’s plea and their lawsuit suggest that his consumption of the edible is what led to Kristine’s death and that, had the warnings been clearer, she’d still be alive.

It’s a major assumption, one that’s not necessarily supported by science, but it’s rocking the first state in the country to legalize recreational use of marijuana. If new regulations on edible packaging in Colorado warn that in some people, the drug could cause them to break with reality, it could prove to be a major blow against marijuana legalization and a boon to people looking for a new defense against a variety of crimes—including murder.

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Kristine called police around 9:30 p.m. on April 14, 2014. She reported her husband was acting strange: crawling in and out of a first floor window for “no apparent reason” and ranting about the end of the world. He’d passed out in their son’s room earlier, she said, forcing her to drag him across the floor. Once awake, he asked if she would kill him.

“Fine, I’ll do it, just give me the gun,” she’s heard saying at one point, apparently trying to disarm him.

Kristine got increasingly anxious as the call continued. She said Richard may have eaten a marijuana edible or taken a pain pill because of his “bad back.” She was afraid he was going to “do something,” and said that her sons were terrified.

“Please hurry,” she begged police.

In the final seconds of the phone call, Kristine is heard pleading:

“Richard, stay away from the gun.

“Richard, please stop.”

There was a scream, followed by a gunshot. By the time police arrived, Kristine was dead.

In the back of the cop car, Kirk admitted without questioning (according to a probable cause statement obtained by local news) to killing her (PDF). Once arraigned, he pled not guilty. Once inside the home, officers found half a small caramel marijuana edible, a Tootsie Roll sized candy that he’d purchased earlier that day. In his blood, they found 2.3 nannograms of tetrahydrocannabinol (THC, the psychoactive ingredient in cannabis). The amount, as one doctor noted in court is “relatively small,” less than half the legal limit to drive in Colorado.

In September 2015, nearly two years after Colorado legalized marijuana, Kirk amended his plea to “not guilty by reason of insanity,” suggesting that the half a marijuana edible he’d consumed earlier had induced an acute psychosis.

It’s a defense that both Kirk and the parents of his slain wife—now the legal guardians of their three kids—have latched onto, one that has the legalization front terrified. In a lawsuit filed this April, Kristine’s parents accuse Kirk of wrongful death and Nutritional Elements (the dispensary) as well as Gaia’s Gardens (the edible maker), of failing to warn of the drug’s potential side effects.

Through this lens, marijuana seems every bit the enemy that the just-say-no to drugs lobby has made it out to be. The scenario is straight out of Reefer Madness: An unpredictable, lethal substance that can provoke a doting husband and father to kill his wife in cold blood. If a judge in the civil trial agrees with this assessment, and implicates the dispensary and edible maker for Kristine’s death, it could significantly hinder the push for legalization.

A ruling in favor of Kristine’s parents would presume that Kirk was driven to kill his wife because of a marijuana edible.

“While nothing can bring their parents back, this lawsuit will seek justice and change in an edible industry that is growing so fast it failed these young kids,” law firm Silverman and Olivas said in a statement to The Daily Beast. “Edibles themselves are not the evil, it is the failure to warn, the failure to properly dose, the failure to tell the consumer how to safely use edibles, that is the evil. And this lawsuit will force change and hopefully get these kids a little justice for being victimized by the rush to profit at the expense of safety.”

It’s a claim that could have huge repercussions in Colorado and muddy the waters of legalization nationwide. But while the argument that the marijuana edible caused Kirk to more or less lose his mind has been widely explored, the potential that it’s a convenient scapegoat has not.

In the complaint filed on behalf of Kirk’s kids, lawyers from the two firms representing them present medical literature and testimony from doctors who confirm that cannabis can in fact induce psychosis. A physician at one of Denver’s largest emergency rooms is quoted saying that too much cannabis can send healthy adults into a panic.

“They will say they see things or hear things that aren’t there,” said Dr. Richard Zane. “They see things on the wall or smell things.” The lawsuit notes that Kirk was examined by three separate experts after the killing, one of whom said that his “level of incapacitation” could not be precisely determined by the THC in his blood.

Unlike alcohol, which can easily be traced in the blood, THC is fat-soluble, meaning that it can be stored in tissues where it goes undetected. Experts have long begrudged the absence of a definitive test to detect THC. Marilyn Huestis, a former chemist at the National Institute of Drug Abuse, told NPR that the current driving limit (5 nanograms) was “arbitrary” and stressed the need for a better system.

Another doctor suggested that Kirk was “vulnerable to distortions in thinking,” but concluded that his personality was “not consistent with a violent or aggressive individual.” The final doctor confirmed that THC was found in Kirk’s blood, and said that video evidence from after the murder confirmed that he was “demonstrating delusional and tangential thinking.”

While much of the evidence supports the idea that Kirk’s thinking was impaired, none mention a potential link between impairment and violence. If anything, the doctor’s testimony points in the other direction, painting a picture of those suffering from acute psychotic episodes as near lifeless and hardly moving. “You can feel like you’re dying,” a representative from a cannabis potency testing lab says of over-consuming.

After noting that edibles have a “ton more THC,” the owner of Colorado’s largest medical marijuana dispensary notes that while over consuming is “very unpleasant,” it doesn’t cause violence.

“If you eat too much marijuana, you have hot flashes and cold flashes and then you get under the covers and pass out,” said Steve Horwitz of Ganja Gourmet. “You don’t start waving a gun around.”

Science has proven that THC can induce an acute psychosis, it has not drawn a link between this psychosis and violence. On the contrary, studies about the drug’s likelihood of causing harm to others show that those using it are more likely to be nonviolent.

One of the earliest comprehensive looks at the link between cannabis and psychosis came in 2007 with systematic review of 35 studies by Dr. Theresa HM Moore. Published in The Lancet, the study concluded that cannabis could increase the risk of psychotic episodes, especially in those predisposed to mental illness, but that researchers had yet to determine why.

Dr. Marie-Josée Lynch, an addiction fellow at Yale University, co-authored a paper on the cannabis-psychosis link in 2012, writing that there was evidence to support the hypothesis that cannabis can induce acute psychotic episodes. She and her co-authors note that the concept itself remains somewhat of a mystery.

“The evidence suggests that cannabis is associated with an increased risk of psychosis when it is used frequently. Whether cannabis can trigger a primary psychotic disorder that would not have otherwise occurred is unclear,” the paper reads. “However, in most individuals who use cannabis, psychosis does not develop, which suggests that the increased risk must be related to other vulnerability factors (genetics, frequency, or age of onset of cannabis misuse).”

Four years later, Lynch says that cannabis use and psychosis remains somewhat of a puzzle in the science world. In an interview with The Daily Beast, she stressed the fact that those with a predisposition to mental illness were more likely to experience psychosis and that even then it’s a small subset of the population.

“It’s difficult because the studies that inform these opinions are massive cohort studies in the Netherlands and Sweden that followed large groups of population for several years,” she said. “There are a lot of confounders, you can’t tell if there are other drugs of abuse and the relationship or if people who have psychotic illness are more likely to smoke marijuana. It’s not crystal clear, unfortunately.”

Beyond outstanding questions about the link, she casts doubt on the idea that cannabis-induced psychosis would result in violence.

“There is not a strong link between psychosis and violence,” she said. “There is a tiny increase when people are psychotic but when you look at large groups of the population it doesn’t pan out. That’s unfortunately not mentioned in the media.” Lynch casts doubt on the idea that psychosis would inspire a husband to murder his wife, and suggests that the media too often pins violence on mental illness.

“Mental illness does not equal violence and most of the violence is not precipitated by mental illness.”

In an interview with CBS in 2015, forensic psychologist Steven Pitt cast further doubt on the psychosis claim.

“The substance-use piece may or may not be a red herring,” Pitt said. “At the end of the day, he’s not going to be found insane because of some edible marijuana he ingested. If he’s legally insane, it will be because he has a mental disease or defect that is separate and apart from his substance use.”

The psychosis link aside, Lynch notes that marijuana is one of the few drugs that is not positively correlated with violence—and is instead linked to the opposite. In 2014 researchers from Yale University, Rutgers, and the University of Buffalo released a study showing an inverse relationship between marijuana and intimate partner violence. The more couples smoked marijuana, the researchers found, the less likely they were to experience domestic violence.

“These findings suggest that marijuana use is predictive of lower levels of aggression towards one’s partner in the following year,” the authors write. The study did not analyze whether using marijuana would reduce the chances of violence on a day-by-day basis, but suggested not only that the drug does not increase violence but decreases it.

On top of questions about whether or not cannabis-induced psychosis could provoke murder are concerns from friends and family that the two were having marital problems. At a preliminary hearing in August 2014, responding officer Troy Bisgard said that friends of Kristine’s told him the couple had been fighting.

Bisgard testified, according to The Denver Channel, that the two owed $2,500 to the Internal Revenue Service and more than $40,000 in credit card debt. They’d fought over his “mishandling a Groupon purchase for hotel stay in Glenwood Springs” and stopped talking for several days. In the weeks before the killing, Kristine had reportedly told a co-worker that her husband had “cursed angrily” and that it left her feeling afraid.

Bisgard declined a request for comment by The Daily Beast, citing the ongoing nature of the investigation.

According to The Denver Post, other friends told police that Kirk had been “verbally abusive” to Kristine and had redirected his paycheck out of their joint account into his own separate one. Another friend of the couple told detectives that Kirk had asked if he could stay at his house, which he reportedly declined.

The statements contradict those from Kirk’s family who, following the incident, called him a “wonderful father” who was devoted to his kids.

“He was hallucinating,” his sister told local news. “It just wasn’t him.”

The link between cannabis use and violence is weak or unsubstantiated, but the link between domestic violence and murder is undeniable. According to the most recent data from the Federal Bureau of Investigation, 35 percent of female murder victims who knew their offenders were killed by their husbands or boyfriends. An estimated 40 percent of these deaths occurred during arguments, the FBI found in the 2014 Uniform Crime Report.

Kristine Kirk was not alone.