Marijuana plants for sale at Studio City's Perennial Holistic Wellness Center.
Federal authorities have arrested a dozen people associated with a chain of nine marijuana stores that operated in Los Angeles and Orange counties, with an indictment alleging the stores didn't report their income to the federal government.
The U.S. attorney's office says the 12 taken into custody Thursday are among 14 named in a drug-trafficking indictment returned by a federal grand jury last week.
Most of the stores had been targets of search warrants executed in 2010 and 2011, and most are now closed.
Prosecutors say the stores generated tens of millions of dollars in income. The indictment alleges that none of the income was reported to federal tax authorities and the owner ordered a bookkeeper to destroy all records about the income.
U.S. attorneys in California are enforcing federal law that doesn't recognize a state initiative that legalized pot for medicinal use.