If his uncle's wife posed any problem, Spyropoulos told the officer to kill her, too, authorities said.
Authorities said a search of Spyropoulos' home turned up two semi-automatic handguns, a shotgun and what the attorney general's office called an "assault-style rifle." Chiesa said six cellphones and several thousand dollars in cash were recovered from the nephew's Mercedes Benz.
Both Spyropoulos, who is originally from Athens, Greece, and his uncle, live in Clifton.
Authorities said the undercover operation was started as the result of a tip from a state police informant.
Chiesa acknowledged that the case played to New Jersey archetypes involving nefarious plans hatched in diner booths.
"This is sort of out of a script right in New Jersey, where you're going to meet at the Tick Tock diner to rub out your uncle to advance yourself," he said. "I understand that reaction of it, but from a law enforcement perspective, we're focused on the safety of the person who is the target."
The classic chrome diner, a popular spot among fans attending Jets and Giants games at the stadium in the Meadowlands a few miles away, is considered a landmark to many people who live or travel along Route 3 in northern New Jersey.
Patrons lunching there Wednesday were shocked by the news.
"It's your basic New Jersey family diner," said Bela Makula, a frequent customer who works nearby. "A standard, New Jersey diner that people try to emulate all over the country."
Asked if he thought the case reflected poorly on the state, Makula replied without a pause:
"Everybody knows that New Jersey is full of criminals and killers."