A selection of marijuana edibles available in Colorado. (Ed Andrieski, Associated Press file)

Few and tricky options for defense attorneys in Observatory Park case

Richard Kirk’s attorneys admit he put a gun to his wife’s head in their Observatory Park home, pulled the trigger and killed her. Tests performed afterward showed he had no alcohol, prescription drugs or other substances in his system — except a low level of THC, the psychoactive element in marijuana.

Now, as details of the bizarre night continue to emerge, the focus of the case shifts to a novel question: Was the marijuana-infused candy Kirk nibbled on enough of the drug to spark a temporary mental breakdown in his ability to tell right from wrong?

Observatory Park husband ate marijuana candy before shooting wife, affidavit says
Richard Kirk was unaware of his surroundings and unable to grasp the consequences of his actions, his attorneys argue.

Legal experts say Colorado’s laws will make it extremely difficult for the 47-year-old to claim the THC in his system that night — described in court as a small amount — made him unable to understand the consequences of his actions. Still, the outcome will be closely watched as lawyers, toxicologists and medical experts grapple with how the now-legal drug affects people differently and whether those reactions can be violent or deadly.

Kirk’s attorneys have not yet entered a plea in the case. During a preliminary hearing last month, they repeatedly argued that Kirk was unaware of his surroundings and unable to grasp the consequences of his actions.

But a Denver judge found that despite Kirk’s erratic behavior on April 14 — diving in and out of a first-floor window, ranting about the end of the world and asking his 7-year-old son to kill him — he still had the ability to unlock the gun safe, load the gun and fire it. The judge ruled there is enough evidence to try Kirk for first-degree murder after deliberation for killing his wife, 44-year-old Kristine.

An arraignment hearing has been set for Oct. 10.

“You can’t just say this is a bad trip,” said Aya Gruber, a law professor at the University of Colorado. “He’s going to have a difficult time fitting into a lot of these defenses.”

Defense attorneys have argued that on the night of the shooting, Kirk did not have the mental capacity to plan to or intentionally kill his wife, which is one of the requirements under the first-degree murder charge.

For certain crimes in Colorado, defendants can argue they were so intoxicated when they committed a crime that they were unable to plan and intentionally commit the act, Gruber said.

In June 2009, Spencer Crawford stabbed a 17-year-old to death during a camping trip, after he started hallucinating when he took LSD and mushrooms and drank “moonshine,” according to the Boulder Daily Camera. Prosecutors eventually dropped the second-degree-murder charge and Crawford pleaded guilty to the lesser count of manslaughter.

Crawford was sentenced to four years in prison.

100 questions about legal marijuana: Colorado info — recreational sales, taxes, rules and regs, the industry and more

But even if Kirk says he didn’t intentionally kill his wife, he still has the difficult task of proving he was intoxicated — a test doctors say is far more complicated for pot, compared with other drugs or alcohol.

Authorities have not revealed the exact level of THC found in Kirk’s blood five hours after he killed his wife, but Denver police Detective Troy Bisgard said the blood test revealed only a low level of THC.

The level of THC in Kirk’s blood at the time it was tested was probably lower than it was when he killed his wife, said Dr. Kennon Heard, who practices emergency medicine at University of Colorado Hospital and teaches at the CU School of Medicine. But unknown factors — such as when Kirk ate the marijuana and whether he had any tolerance for the drug and any digestive issues — make it difficult to determine when the effects of the drug were strongest.

Heard said peak levels are harder to determine when people eat marijuana, compared with when people smoke it. Every month, Heard sees a handful of people in the emergency room dealing with anxiety because of marijuana intoxication, but he rarely sees anyone become aggressive.

Edibles testing: Lab analysis of THC potency is now mandatory

If Kirk wants to argue the marijuana stopped him from understanding the consequences of his actions, he could enter a plea of not guilty by reason of insanity, and then his attorneys will have to show the drug triggered some kind of underlying mental health condition, said Russell Covey, a law professor at Georgia State University.

In that scenario, Covey said, a low level of THC in Kirk’s blood would help in his defense.

“It suggests that the cause of his crazy behavior was not being stoned but rather a pathological reaction to the drug that was unanticipated,” Covey said.

Jordan Steffen: 303-954-1794, jsteffen@denverpost.com or twitter.com/jsteffendp

This story was first published on DenverPost.com