CLIFTON, N.J. — Explaining the success of Greek diners to an interviewer 15 years ago, Alex Sgourdos talked about “kerdos” — profit — and family. “To show you’re Greek, all you have to do is work 12 hours a day and have lots of relatives who like the business and work with you,” he said.

As he and his brothers-in-law turned the Tick Tock Diner into one of the most famous in a state known for its diners, they not only worked together shuttling burgers and homemade pie to customers, but they also vacationed together and raised their children and their children’s children within blocks of one another.

Now, prosecutors say profit and family are behind the attempted murder of Mr. Sgourdos.

His nephew, a manager at the diner, is charged with hiring a man to kill Mr. Sgourdos, with instructions to torture him first until he surrendered the combination to the diner’s safe — and the money his nephew believed Mr. Sgourdos was hoarding.

“Not enough to satisfy yourself, to let everyone be happy, too,” the nephew, Georgios Spyropoulos, complained to a man he believed was a hired killer — actually an undercover state trooper — as they sat at the diner in March, according to the official arrest affidavit. “Out of nine families, the other eight suffer because of him.”