Fear City: New York City vs the Mafia takes a look at the 70s and 80s — a bloody era in New York when five mafia families had a massive financial hold on the city and committed countless crimes to keep it.

But the heroes of the three episode docuseries, now streaming on Netflix, are the FBI men and women, including prosecutors, who took the city back. Many of them reflect on that turbulent time, and so do former members of the mafia.

“The people we were working with said certain certain mobsters will not talk," explained director Sam Hobkinson. "Don't even try, you know? They're hardcore till they die. Certain other mobsters have turned state's witness. They’re more sort of out there and they’ve written books and are a little bit more accessible.”

The series shows how the FBI and prosecutors used the federal RICO Act to go after the heads of the five mafia families.

The FBI bugged homes, restaurants, cars and more to collect the evidence they needed. Bronx native Joe Cantamessa was the undercover FBI agent for the job.

“My father worked for a major construction company in New York City and I got to learn from the inside," he said. "As to how things were really being conducted way before I became an FBI agent."

One key entry was into the home of Paul Castellano, who was head of the Gambino crime family in the 80’. Cantamessa remembers that day.

“His presence there and then he pretty much stepped out, and then I was left with the older gentleman and Tommy Bilotti, who were there to watch me or keep an eye on me," he said. "And I basically made sure that I brought my New York Bronx attitude with me.”

Fear City shows how prosecutors proved that orders came from the very top of these mafia families. That led to convictions and prison sentences of 100 years across the board.