ROSEVILLE (CBS13) — Legalized pot in California is leading to changes in some local police K-9 units, and the dogs trained to detect marijuana.

“Once you train a dog on something you can’t untrain them,” Roseville police officer Scott Miszkewycz said.

Roseville police are training new dogs that won’t detect the smell of marijuana.

Lance is a 2-year-old German Shepard that will be Roseville’s first drug-sniffing dog that won’t alert handlers to marijuana, only to heroin, cocaine and methamphetamine.

“Now they will not be trained on marijuana, they’ll be trained on the other three,” Miszkewycz said.

Lance is Roseville’s solution to the problem California created for law enforcement when the state legalized pot. The decision created an industry of over-qualified drug-sniffing dogs, no longer needed to alert handlers to now legal marijuana.

“Obviously the dogs have a career, a lifespan that they’re used for, so we’re faxing them out. Once they retire out, we’re not trying the new dogs on marijuana,” Miszkewycz said.

Besides Lance, Roseville plans to bring on three other new drug-sniffing dogs for their illegal drug searches.

Until then, K-9s currently on the force will be kept out of drug searches and only used in other law enforcement roles.

“Building searches, area searches, tracking,” Officer Miszkewycz said.

It’s just one of the changes coming from California new era of legalized marijuana.

“It’s a brave new world,” defense attorney Jeff Kravitz said.

Kravitz says California’s decision to legalize pot is not only changing policing of marijuana, it could also lead prosecutors to file fewer cases involving drugs that remain illegal.

“Because they can sense that the juries won’t care,” Kravitz said. “And so they don’t want to prosecute cases that the juries don’t care about.”

Questions surrounding the wide-ranging impacts of California’s new legal pot laws.

From the courtrooms to K-9 officers and their companions.

In Roseville, the answer starts with new training for their drug-sniffing dogs.