(KRON) -- What began as a traffic stop for a stolen registration sticker in San Rafael Saturday led to a suspect being arrested on drug charges. A San Rafael Police Department officer observed a vehicle just after midnight with a stolen registration sticker. San Jose driver used plastic skeleton as passenger for HOV lane The vehicle's actual registration, according to police, was expired. After stopping the vehicle and making contact with the driver, the officer noticed a passenger in the vehicle had an open container and observed drug paraphernalia. Photo: San Rafael PD The officer subsequently detained both the driver and the passenger. A search of the occupants and the vehicle revealed a "substantial amount" of cocaine and fentanyl, police said. Further investigation revealed that the passenger was the vehicle's registered owner. The driver, it was found, wasn't involved with the narcotics or the stolen registration sticker and was released. Police arrested the passenger and booked them into jail for: Transporting narcotics for sale Possession of narcotics Possession of drug paraphernalia Stolen vehicle registration "This was great police work," said San Rafael PD in a social media post. "With the current Fentanyl crisis, we are proud that our officers are making efforts to remove this dangerous drug from our community's street."