Wondering why your doctor only works weekends? It could be because he or she isn't a licensed doctor at all — or, as police believe to be the case in King City, Calif., your physician also ships in drugs and supplies illegally.

Two brothers were arrested Sunday and remain in jail on charges of posing as doctors and operating an unlicensed medical practice out of a rented King City garage for as long as 18 months, the Monterey County Herald reported.

But despite the shady weekend hours and the unconventional office, the makeshift medical facility, catering mainly to farm workers, still managed to get "cars just lined up" outside, King City police Sgt. Bobby Carrillo told the newspaper.

Jaime Navarrete of Brawley and Francisco Navarrete of Mexicali, Mexico, face a variety of charges, including practicing medicine without a license, possession of a hypodermic needle and conspiracy, the newspaper reported. They reportedly were still in Monterey County Jail, unable to post bail at $150,000 apiece.

Investigators said the brothers saw patients on Saturdays and Sundays in the vacant rental home, charging $30 to $45 for consultations and more for pharmaceutical drugs. They stored prescription drugs brought from Mexico and other medical supplies at another house, Carillo told the press.

The duo even set up an exam table, a pharmacy and an eye chart, Carillo told the newspaper. Police said they believe a wide variety of pharmaceutical drugs were made in Mexico, along with stethoscopes, syringes and blood-pressure cuffs.

The investigation into the goings-on at the residence in the 500 block of North Mildred Avenue began several months ago after police received an anonymous complaint from a resident upset by all the traffic at the home, the newspaper reported.

Carrillo told the Salinas Californian newspaper that in their search, investigators found stationery that identified Francisco as a physician as well as a bulk of illegal pharmaceuticals from vitamins to Viagra, hypodermic needles, medical equipment and more than $4,200 in cash and checks.

Police kept surveillance on the garage and the storage area for separate three- to four-hour occasions, where they found that the brothers averaged 30 to 40 patient visits, both papers reported.

But because none of the Navarrete brothers' customers have come forward, Carillo said the police are uncertain how many people were affected.

More charges were expected upon further investigation.

The Associated Press contributed to this report.