Members of a Bronx-based drug ring distributed millions of doses of fentanyl, heroin, and cocaine throughout New York City and delivered on demand to buyers in the advertising and real estate industries, law enforcement officials say.

Authorities unveiled charges against 16 people on Monday. Of them, 11 were arrested on November 15 and the others were already in custody, officials say.

In addition to the arrests, during the six-month probe investigators from the DEA, NYPD, New York State Police and U.S. Homeland Security seized 12 kilograms of fentanyl, 6 kilograms of heroin, 3 kilograms of cocaine and more than $175,000 in cash, the officials say.

The state charges filed by the Bronx District Attorney’s office include possession and sale of a controlled substance, money laundering and conspiracy. Four of the individuals are charged with operating as a major trafficker and face life in prison if convicted.

"This transnational drug trafficking crew made the Bronx an epicenter of fentanyl distribution," said DEA Special Agent in Charge James Hunt in a statement. "Through coordinated enforcement on federal, state and local law enforcement levels, traffickers responsible for smuggling heroin, cocaine and six million fatal doses of fentanyl into our city have been arrested."

"Deadly fentanyl coupled with recreational cocaine sales shows that this group was as versatile as it was vicious," Bronx District Attorney Darcel Clark said. "They allegedly drove the narcotics up the eastern seaboard from Florida, bringing the attendant misery to the Bronx, Manhattan, Westchester County and New Jersey."