Sergio Roblero, 19, said he had paid a recruiter in Mexico $4,480 for a guest worker’s visa and travel expenses to pick blueberries in Georgia. He was told he would be making $10.59 an hour; he made only $3, he said. Mr. Roblero was unable to leave the farm unless he paid $1,000 to get his passport back. To recoup his losses, he moved four months ago to Buffalo, where a friend from Mexico was working for Mr. Mucino’s restaurants.

“I’m afraid that other people are going to go through what I did,” Mr. Roblero said. “I know that the economy in Mexico is always going to be bad and people are always going to come to this country.”

According to statistics from 2014 released this month by the Pew Research Center, nearly eight million undocumented people in the United States were part of the work force or seeking employment. In New York State, undocumented immigrants represented 6 percent of the labor force.

While some of his workers are still detained, Mr. Mucino was released on $85,000 bail and reopened La Divina, though his other restaurants, which are full service, remain closed.

Mr. Mucino parked a black Mercedes sport utility vehicle behind the store last week and spoke of his employees. “All of them are very nice people and they’re hard workers,” he said. “I feel very bad for everything that happened.” He declined to comment further on the charges.

According to the authorities, an incident in August accelerated the investigation. Fourteen men went to play basketball after their shifts around 10 p.m., at a suburban Buffalo playground.

The local police answered a call about the group and asked for identification. When some of the men could produce only Mexican identification cards, the police called the United States Border Patrol. By 1:30 a.m., 10 people were detained and five were arrested, charged with having illegally re-entered the country.