Trying to cash in on gold fever, a California precious metals trading firm teamed up with South Florida telemarketers to fleece investors, who thought they were buying precious metals but ended up with nothing, according to federal regulators.

U.S. District Judge Donald M. Middlebrooks in West Palm Beach on Friday granted a preliminary injunction sought by the U.S. Commodity Futures Trading Commission to freeze the assets of 12 related companies and assigned Miami attorney Melanie Damian as a special monitor and corporate manager. Nine executives of the companies also are defendants in the civil action.