In the wake of last year’s cannabis legalization in Missouri, law enforcement agencies in the state are reporting that many drug-sniffing police dogs trained to detect marijuana may face an early retirement.

Police say the dogs, due to their sensitivity to the odor of cannabis, can compromise investigations and hinder successful drug prosecutions. According to police officials, dogs that are trained to detect marijuana are often unable to separate scents for their handlers, making it difficult to distinguish between a single joint and an unlawful quantity of marijuana or other illicit drugs nearby.

Sergeant William Brown of the Kansas City Police Department explained the legal issues that can arise from this situation.

“A defense attorney is going to say, ‘Your dog hit on marijuana’ if there’s even one joint, no matter if there was cocaine or whatever else alongside it.”

To address the problem, many agencies are choosing to retire dogs and training new ones exclusively for identifying illicit drugs.

As early as 2018, the Boone County Sheriff’s Department anticipated the impact of legalizing cannabis on its K-9 units and stopped cannabis training for its dogs.

“We had the forethought to stop training marijuana on dogs several years back,” Captain Brian Leer told the Columbia Missourian.

The department also took measures to reduce the cost of purchasing and training new canines, as procuring dogs for police work is typically expensive — ranging from $9,000 to $10,000 each, not including training costs.

The Boone County Sheriff’s K-9 program managed to circumvent this problem by offering an affordable eight-week training course costing $4,000 per dog.

This significantly reduced expense has attracted law enforcement agencies, including the Columbia Police Department, which is currently replacing two dogs using a grant from the Missouri Department of Public Safety called the Canine Replacement Grant.

As part of the training course, handlers hide small baggies containing various substances and have the dog locate them, gradually progressing to “blind searches” where neither the dog nor the handler knows the location of the substances. Dogs can even learn to detect drugs in vacuum-sealed bags and eventually advance to more challenging tasks like scent-tracking and aggression training.

However, some agencies are still hanging on to their marijuana dogs while awaiting grant money to purchase new dogs.

“Some agencies are waiting to get in on the DPS grant, and they’re still using their dogs that are marijuana-trained because there’s no case law yet,” Boone County Officer and K-9 trainer Chris Smith said.

Certain law enforcement agencies, such as the St. Louis Metropolitan Police Department, have determined that their dogs can continue to serve without risking illegal searches. Some of their K-9s possess skills in multiple areas, such as bomb detection and suspect tracking.

The interpretation of Amendment 3, which governs legal cannabis in Missouri, is still in its early stages. Consequently, some handlers are opting to wait for court interpretations before adjusting their procedures. According to Sergeant Charles Wall of the St. Louis Metropolitan Police Department, until there is clear case law indicating otherwise, they believe that the odor of marijuana can still establish probable cause for searches in specific situations.

“The fact that we say we can’t use the dog to develop probable cause — there’s not case law yet where the courts have actually said ‘you can’t do this,’” Wall said.

“It is our interpretation of Amendment 3 that the odor of marijuana may still establish cause to search in certain situations.”

Legal expert Dan Viets, an attorney and Missouri coordinator for the National Organization for the Reform of Marijuana Laws, believes that the use of marijuana dogs is already meaningless from a legal standpoint. Viets argued that searches by state law enforcement based solely on marijuana, regardless of probable cause, will be deemed illegitimate by the courts.

“If they’ve obtained specific evidence to pursue a search on what they suspect to be illegal marijuana, they don’t need a dog,” Viets said.

As for retired K-9s, they often remain with their handlers’ families. For instance, Nero, a 6-year-old Belgian Malinois from the Columbia Police Department, is retiring but will continue to live with his handler, Officer Eric Wiegman.

“My kids wouldn’t know what to do without him at home,” Wiegman said.