The sheriff's office said the probe began in December when investigators received a tip about cocaine being sold out of a Papa John's eatery in Sammamish.
Undercover investigators determined two workers at the pizzeria were using and selling cocaine while at work and would deliver the drugs in pizza boxes in the restaurant's parking lot.
"We sent undercover detectives in there and sure enough our undercover detectives were able to establish a relationship with a couple of these drug dealers," King County Sheriff's Sgt. Cindi West told KOMO-TV.
The sheriff's office said the employees introduced the undercover deputies to other drug dealers in Sammamish and Bellevue when they were out of cocaine.
Detectives executed a search warrant at the restaurant early Friday morning. Cocaine residue was detected at a sink, on soap dispensers, and the cash register. Police said no drug residue was found in food-prep areas.
Police also searched other locations in Sammamish and Bellevue Friday as part of the investigation.
The searches led to the seizure of $28,000 in cash, a vehicle, and drugs including cocaine, ecstasy, marijuana, Oxycodone, LSD, and methamphetamine.
"Papa John's has zero tolerance for this type of offensive and illegal behavior. The franchise has confirmed that the employees involved with this situation are no longer employed and we apologize for their actions," the pizza chain said in a statement.
King County Public Health said it was assisting the eatery with clean-up.
