OAKLAND -- Police seized guns, cash and a cache of stolen goods from a suspected gambling house on International Boulevard, officials said Wednesday.

The suspected illegal gaming and fencing operation was shut down Friday afternoon when more than a dozen officers led by Sgt. Frank Rojas executed a search warrant at the business on the 600 block of International Boulevard.

Police found two semiautomatic rifles, four handguns, more than $13,000 in cash and methamphetamine. Also seized were 20 gambling machines, 12 of which were hidden in a secret back room, according to police. The guns were legally registered, police said.

Additionally, officers discovered hundreds of dollars worth of suspected stolen items, including 20 "high-end" bicycles, guitars and other instruments, numerous cellphones and tablets, car radios and speakers, and car rims and tires, according to police. Physical and electronic records of who won money and who owed money to the gaming house were also recovered, authorities said.

More than a dozen people were detained, but only seven have been charged so far, including four employees facing illegal gambling charges. They are security guard Ol Norng; Anh Mac, of San Pablo; and Oakland residents Ngoc Nguyen, 43 and Vu Nguyen, 51. Katherine Marquez and Rudy Agtarap were charged with possession of methamphetamine, while Long Ta was charged for illegally possessing a gun.

The business, purportedly a cafe located in a strip mall, was closed Wednesday. Police said the gambling house brought in anywhere from $50,000 to $80,000 a month and operated nearly around the clock seven days a week.

Attempts to reach the business owner were not successful.

David DeBolt and Harry Harris cover breaking news.