Did Marijuana Make Him Do It?

The Denver homicide that became a prohibitionist cautionary tale

Between 1911, when Massachusetts became the first state to ban marijuana, and 1937, when Congress made pot prohibition the law of the land, cannabis acquired a reputation as a "killer drug" that drove people to irrational acts of violence. Since 2012, when Colorado became the first state to repeal its ban on marijuana, that quaint notion has made something of a comeback, mainly due to the April 2014 death of Kristine Kirk, a 44-year-old Denver mother of three, at the hands of her husband, Richard.

Richard Kirk's shooting of his wife, which happened at their home during a 911 call in which she described  his bizarre behavior after eating THC-infused taffy, is routinely cited by pot prohibitionists as an example of what other states can expect if they legalize marijuana. Kirk himself, who this month pleaded not guilty by reason of insanity, seems keen to blame his actions on a product that his lawyers have suggested left him incapable of forming the intent required to be convicted of first-degree murder. But as is always the case when violence is attributed to a substance used by millions of people who never hurt a fly, the story is more complicated than the cautionary tale told by anti-drug propagandists.

According to the police affidavit supporting a warrant to search Kirk's Chevrolet Suburban, he drove to Nutritional Elements, a marijuana store on South Colorado Boulevard in Denver, around 6:30 p.m. on April 14, 2014. He left the store about 10 minutes later with a Bubba Kush joint and a piece of Karma Kandy Orange Ginger taffy. The taffy contained about 100 milligrams of THC—a big dose for an inexperienced user, which is how a clerk at the store described Kirk, who was then 47 and is now 49. According to Kirk's public defender (who has since been replaced by a private attorney), the clerk recommended that he eat just one-tenth of the taffy, or 10 milligrams of THC. KUSA, the NBC station in Denver, reported last March that he ate the whole thing. But The Denver Post reports that he ate only "nibbles" and that police found the "partially eaten" candy in the Kirks' home.

Kristine Kirk called 911 about three hours after her husband bought the taffy. She reported that he was "totally hallucinating" after consuming marijuana, possibly combined with a prescription painkiller. Police said Kirk was "scaring their three small children," "talking about the end of the world" and urging Kristine to shoot him.

"Don't go in there," Kristine can be heard saying about 12 minutes into the 911 call, according to police testimony. "Stay away from the gun." A few seconds later, she says, "He's getting into the gun safe." Soon she can be heard pleading, screaming, and running. Less than half a minute after Richard gets his pistol, there's a gunshot, and nothing more is heard from Kristine.

Police arrived seven minutes later to find Kristine lying on the floor, dead from a gunshot wound to the head. On the way to the police station, according to the search warrant affidavit, Richard Kirk was "rambling to himself" and at one point spontaneously announced that he had killed his wife. His public defender, by contrast, said Kirk was still confused about what had happened, asking police to let him call his wife.

At Kirk's preliminary hearing in August 2014, prosecutors argued that his ability to remember the code for his gun safe, unlock it, retrieve the pistol, and put the weapon to his wife's head demonstrated that he knew what he was doing. Denver Detective Troy Bisgard testified that the Kirks had been fighting a lot in the weeks before the shooting, to the point that they did not speak to each other for days. Bisgard said Richard asked a friend to put him up for a while, and Kristine confided to a friend that she was afraid of Richard. The couple had more than $40,000 in credit card debt and owed another $2,500 to the IRS. Richard had recently changed the automatic deposit of his paycheck so that the money went into his bank account instead of the one he shared with Kristine. He stood to benefit from a $340,000 life insurance policy in the event of Kristine's death (although not if he was identified as her killer).

Bisgard also testified that THC was the only drug detected in Kirk's blood and that the level was "relatively low." The Denver Post reports that the THC concentration was just 2.3 nanograms per milliliter, less than half the level that is presumed to impair drivers under state law (but which may not in fact indicate impairment, especially in regular users). Assuming Kirk was an infrequent cannabis consumer, it is still possible that he ingested enough THC to have an unpleasant experience. But bad trips rarely end in homicide.

In a report submitted by the defense last August, a physician said the THC that Kirk ingested had triggered a psychosis-mimicking delirium. The relevance of that conclusion to Kirk's defense is unclear, however, since under Colorado law "the voluntary ingestion of alcohol or any other psychoactive substance" cannot be the basis of an insanity defense. Rather, a defendant must show that a "mental disease or defect" rendered him "incapable of distinguishing right from wrong" or incapable of "forming a culpable mental state."

A psychologist hired by the defense reported that Kirk "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." Before his next hearing, which is scheduled for December 17, Kirk is supposed to receive a psychiatric evaluation at the Colorado Mental Health Institute in Pueblo.

In short, instead of a mild-mannered guy transformed into a murderer by marijuana, we have a man who had been bitterly fighting with his wife for weeks, who seemed to be contemplating a separation if not a divorce, and who, according to his own lawyer, was unstable psychologically as well as financially. Was too much THC the essential ingredient that made this toxic stew lethal? The answer is unknowable, just as it would be impossible to say whether the influence of alcohol made a crucial difference if Kirk had been drinking that night.

Fortunately, that is not a question opponents of pot prohibition need to answer. If drunken killers do not clinch the case for banning alcohol, stoned killers (who seem to be much less common) cannot clinch the case for banning marijuana. Nor is marijuana's impact on Kirk a question a jury will have to address in deciding whether he should be held responsible for his actions. Colorado's law says people are responsible for the effects of psychoactive substances they deliberately consume, and according to Kirk's attorney he chose to take more than the recommended dose.

If Kirk's lawyers are hoping anti-pot prejudices will work in their client's favor, they are apt to be disappointed. In 1937—the year that Congress effectively banned cannabis nationwide by passing the Marihuana Tax Act, when fear of the "killer drug" was surely stronger than it is today—a 20-year-old New Jersey woman named Ethel Strouse Sohl, together with a 17-year-old accomplice named Genevieve Owens, held up a bus driver in Newark. When the driver tried to grab Sohl's sawed-off rifle, she shot and killed him. She and Owens got away with $2.10 in change. At their trial Sohl's lawyer argued that she should not be held responsible for her actions because she was suffering from "marijuana madness" at the time of the robbery. She testified that the "marijuana cigarettes" she smoked before the bus holdup and two previous robberies "made wrong things seem right."

The jury did not buy it. Sohl and Owens were convicted and sentenced to life at hard labor. Perhaps the jurors were swayed by prosecutor William Wachenfeld's warning during his summation. "Marijuana never had anything to do with this case," he said. "If you men open the door to a fantastic defense of this kind, it will be all right for anyone to commit a murder if only he first smokes marijuana."

This article originally appeared at Forbes.com.