LAUREL COUNTY, Ky. (WKYT) - WKYT has been tracking the investigation all day into a discovery that shocked shoppers the day before Thanksgiving.

Police in Nicholasville had to evacuate a Walmart after someone found a meth lab in a restroom. So WKYT wanted to know, how often do police find mobile meth labs in public places? Should you be on alert?

Nicholasville police called Wednesday's discovery of a mobile meth lab inside Walmart a rare one. One county sheriff agrees. They bust more meth labs inside homes in Laurel County than they do mobile labs.

"They're easy to conceal, and normally the only thing that will give them away if they are in plain view or maybe the smell of an actual lab cooking," explained Laurel County Sheriff John Root. Sheriff Root has only found two mobile meth labs in his two years in office.

"One was actually in a backpack that was found here by the Sheriff's Office and one was in the trunk of a vehicle."

Sheriff Root says they don't deal with a lot of mobile meth labs because they're smaller and harder to find.

"You could be sitting right next to a car that's got a active lab in it and not know it."

In all, WKYT talked to officers in Nicholasville, London, and Richmond. They say they often get lucky finding mobile meth labs. Sometimes, it's the suspicious behavior they spot first, sometimes it's the smell.

"It's hard for the person that's actually operating the meth lab to get rid of that smell. It's a very distinct smell," notes Sheriff Root.