SAN DIEGO -- Agents from the Internal Revenue Service Wednesday searched the headquarters and a warehouse of diet supplement company Metabolife International.

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'We Don't Know What They're Looking For'

The warrants were sealed by a federal judge and authorities declined to disclose the focus of the daylong search.

"It's an ongoing investigation," said IRS Special Agent Tami Stine. No immediate arrests were anticipated, Stine said.

The company, which makes herbal and dietary supplements, said it was cooperating with the IRS inquiry.

"We understand that the Internal Revenue Service is conducting a tax investigation having nothing to do with Metabolife's products," the company said in a statement. A spokeswoman declined further comment.