In what began with a four-year-old case against a franchisee in Long Island, New York, agents targeted about 100 7-Eleven stores nationwide to open employment audits and interview workers. President Trumps sharp expansion of immigration enforcement has already brought a 40 percent increase in deportation arrests. Illegal hiring rarely is prosecuted, partly because investigations are time-consuming and convictions are difficult to achieve because employers can claim they were duped by fraudulent documents or intermediaries. The 7-Eleven stores served on Wednesday will be required to produce documents showing they require work authorization. Audits may lead to criminal charges or administrative penalties.