Canine cops who are trained to sniff out cannabis odor may be on the unemployment line in Colorado soon. A judge in the Colorado Court of Appeals has ruled that dogs trained to detect weed among other controlled substances cannot be trusted to delineate between criminalized and non-criminalized drugs, and therefore cannot be used to warrant probable cause.

The case in question is the arrest of Kevin McKnight in Moffat County. In 2015, drug-sniffing dogs alerted officers to the odor of drugs inside McKnight’s truck. When police then searched the truck, they found a meth pipe and McKnight was charged with possession of drug paraphernalia and possession of a controlled substance, as reported by Leafly.

But the recent decision by the Colorado Court of Appeals reverses the conviction. The judges ruled that since cannabis is legal for adults over 21 in Colorado, a dog who may be alerting officers to its smell cannot provide sufficient probable cause that a crime has been committed.

“A dog sniff could result in an alert with respect to something for which, under Colorado law, a person has a legitimate expectation of privacy,” read the ruling.

“Because a dog sniff of a vehicle could infringe upon a legitimate expectation of privacy solely under state law, that dog sniff should now be considered a ‘search’ … where the occupants are 21 years or older.”

Courts in Colorado have ruled the other way before. A State Supreme Court case last year ruled that, though marijuana was not criminalized in Colorado, the odor of marijuana is still suggestive of criminal activity,” and could “contribute” to probably cause if there is other observable suspicious behavior.

Since McKnight did not exhibit suspicious signs such as inebriation, the drug-sniffing dogs were never called for in the first place, according to the Court of Appeals judges.

In other states with legal medical cannabis, such as Arizona and California, courts have ruled that the smell of marijuana cannot alone provide probable cause for a search.