While the storied Italian Mafia has lost its stronghold in the United States, its progeny remain alive and active with an estimated 3,000 members and affiliates. The FBI still calls La Cosa Nostra “the foremost organized criminal threat to American society.”

Yet organized crime networks have shifted dramatically since the Mafia’s heyday. Major crime families are replaced by an intricate web of foreign nationalities that engage in everything from wire fraud to computer hacking and human trafficking. And although the FBI’s siloed response evolved to a broader interagency cooperation, numerous syndicates snake under the radar and give law enforcement a headache.

Today, “the loyalties are gone. There used to be big bosses, under-bosses and soldiers. It is a much younger crowd now with smaller cells, and everybody turns on each other,” said Eric Schneider, a former associate of kingpin Whitey Bulger and Boston’s Irish mob. “The ongoing attraction to organized crime is still probably a byproduct of the past two decades of people growing up with ‘Goodfellas’ and aspiring to that life, which I don’t understand now.”

Real-life and fictional gangsters continue to resonate powerfully in film and television – from Bulger biopic “Black Mass” to “American Hustle” to Esquire Network’s upcoming scripted drama series “Spotless.”

Schneider worked with Bulger from 1986 until 1993 when he was arrested. To avoid a life sentence, Schneider testified against his partners. “I went against what I was brought up with – the code of silence – you kept your mouth closed.” His partners went to prison and he spent 20 years in witness protection. He recently revealed his identity in his book "The Choir Boy."

While in decades past the FBI chased Italian and Irish mobsters, it now pursues criminals of multiple nationalities, including those who target U.S. citizens online from abroad. Since many crimes now happen online, the FBI heavily recruits tech experts and cybersecurity agents for electronic surveillance.

The laundry list of organized crime in the United States is ever-growing. Adding to the traditional racketeering activities of old are drug and human trafficking, tax fraud, hacking, identity theft, securities and investment fraud, sale of untaxed merchandise and counterfeit goods, and fraudulent mortgages, insurance, credit cards, food stamps and baby formula.

Groups often cooperate across ethnic and racial heritage lines, and co-mingle their illegal activities with legitimate business ventures. They’ve been identified in more than 50 metropolitan areas in the United States.

Much U.S.-based organized crime has roots in families, tribes or clans in originating countries. These structures strengthen networks and perpetuate the cycle of crime. In response, the FBI dedicates its organized crime units to different ethnic and geographic categories – Italian, Asian, African, Eurasian and Middle Eastern.

The FBI lacks undercover agents who speak the native language of communities and can infiltrate them without suspicion. “We don’t have enough agents who speak the languages fluently,” said Anthony Brizzolara, a retired special agent and 32-year FBI veteran. “We rely more on physical and electronic surveillance.

The good news is that the Racketeer Influenced and Corrupt Organization federal law of 1970 (RICO) has allowed agencies to significantly gut entrenched networks like the Italian and Irish by prosecuting syndicate leaders for crimes they commissioned.

With RICO, law enforcement can attack an entire entity instead of imprisoning individuals, who can easily be replaced with other associates. “RICO all but destroyed traditional organized crime in America,” said Robert Lombardo, associate professor of criminology and criminal justice at Loyola University in Chicago.

“The law gave us a lot more power and ability to affect change and eventually get people to roll over,” Brizzolara said. “Once the dam broke as higher level folks ‘turned,’ over time more turned, which helped turn the tide for us against [the Italian Mafia].”

Yet new opportunists are always looking for ways to skirt laws. Brizzolara noted that illegal immigrants who enter through Canada and Mexico from around the world continually feed existing criminal networks. “The common denominator is that a lot of money is being funneled back to home countries, with entire families involved” in both public nuisance crimes and violent crimes like drug and human trafficking.

“The FBI and other agencies target these groups and make arrests, and often the major players get deported. Six months later, they show up on surveillance. They are adept at getting back into the country,” said Dennis Franks, former FBI special agent and managing director at Risk Control Strategies in Houston.

Just last year, federal, state and local officials staged a major money laundering takedown of the Sinaloa drug cartel in Los Angeles. “Mexican drug cartels are the most important organized crime challenge that we face. The DEA are the unsung heroes in the effort against the cartels,” Lombardo said.

Interagency alliances against organized crime began to appear after the passage of RICO and have flourished in the post-9/11 era. “I like to think it’s changed a lot since I became an agent 32 years ago. It’s 100 times better in terms of sharing and working with other agencies. It’s better to work together and not stovepipe things,” Brizzolara said.

Now that Bulger is in prison and the Boston Irish mob appears a distant memory, American groups without native ties overseas are more concentrated in home-grown hate or terrorist cells that work for political or social purposes, Brizzolara said. Although, “our prison system is a wonderful breeding ground for getting folks together who are incarcerated and of like minds to coalesce.” And that is true for criminals of any background.

Whether it’s cartels, La Cosa Nostra or any insidious operation, loyalties do not always prevent groups from forming outside alliances. For example, Colombian and Mexican cartels have collaborated to smuggle cocaine to the United States. “While they might fight with each other within their country or their organizations, they become quite adept at being able to collaborate with other criminal groups,” Franks said.

“Any groups can learn to adapt if it makes sense business wise.”

Watch how organized crime comes between two brothers on “Spotless,” premiering Nov. 14 on Esquire Network.