The CHP served a warrant on a Santa Rosa gas station and convenience store Tuesday afternoon on behalf of the state Board of Equalization, but the tax agency would not say what its agents were looking for.

Workers from the Board of Equalization, which collects the state's taxes and fees, were visible between 3 p.m. and 4 p.m. in the parking lot of the Am-Pm store at corner of Fourth Street and Brookwood Avenue. The business was closed and guarded by a CHP officer. The BOE workers, who were wearing black shirts with the agency's initials on the back, appeared to be piling boxes of records near a van parked in the lot.

In a written statement, the agency said it "is prevented by law from releasing taxpayer information." A spokeswoman declined to discuss the raid or even to confirm the location where the warrant was served.

The agency statement said BOE was "coordinating" with the police departments of Vancouver, Wash., and Tigard, Ore., but did not explain why.

A man who answered the phone at the store later in the afternoon declined to comment but said the business had reopened.