The defendants entered each employee’s personal information and hours worked into computer terminals at the stores. The parent company processed the payroll and sent the wages to the employers for distribution. The defendants, officials said, never paid the workers all that they were due.

Instead, prosecutors said, they might have earned $300 to $500 per week for 100 hours of work.

Ms. Lynch said the employees “were not innocent victims in this scheme,” but added that they had been abused. Agents from ICE had interviewed some of the illegal immigrants and, for now, were treating them as potential witnesses and were not seeking to move to deport them, Mr.Picard said.

Investigators have not found a connection between the two families, suggesting that the knowledge of how to exploit the payroll system could have been widespread and the ongoing investigation is based on payroll records provided by the parent company. Prosecutors are seeking $30 million in forfeiture from the stores and the corporate parent.

The charges were announced at a news conference by Ms. Lynch and James T. Hayes, who is in charge of ICE’s office of investigations in New York City, along with officials from the New York State Police and the Suffolk County Police Department.

“From their 7-Eleven stores the defendants dispensed wire fraud and identity theft, along with Slurpees and hot dogs,” Ms. Lynch said. “In bedroom communities across Long Island and Virginia, the defendants not only systematically employed illegal immigrants but concealed their crimes by raiding the cradle and grave to steal the identify of children and even the dead.”

Ms. Lynch said the defendants “ruthlessly exploited their immigrant employees,” forcing them to live in unregulated boardinghouses and “creating a modern -day plantation system.”

In one instance, an employee of one franchise was paid using the Social Security number of a former 7-Eleven employee, a person who had not worked for the store for 10 years and who had been the target of collection efforts by the Internal Revenue Service for much of that time because of the reported payments to the illegal immigrant, officials said.