LEXINGTON, S.C. — The weekday lunch rush arrives as a small ritual of suburban pleasure at the San Jose Mexican Restaurant, just across from the tanning salon and the strip-mall multiplex. A mostly white clientele pulls into a parking lot, past a sign with a cartoon peasant tugging on an obstinate donkey. Inside, a mostly Latino work force serves Americanized versions of Mexican classics as a sound system plays syrupy Spanish ballads.

The restaurant chain — local, family-owned and, with more than a dozen locations, as abundant here as any national brand — has been around central South Carolina since the days when Tex-Mex was considered exotic.

Today, it is at the center of an illegal immigration and bribery scandal that has resulted in the indictment of the state’s longest-serving sheriff, who has showcased the deportations of hundreds of people not authorized to be in the country.

A June 17 grand jury indictment accuses Sheriff James R. Metts, Lexington County’s top law enforcement official since 1972, of accepting cash bribes from Gregorio M. Leon, a 47-year-old restaurant mogul whose family founded the first San Jose restaurant in the state in the late 1980s. In exchange for the cash, Sheriff Metts, who pleaded not guilty this week, is alleged to have freed restaurant workers arrested in an initiative against illegal immigration and sent to the county jail he controlled.