The largest heroin bust in New York history, and fourth-largest in the country, was traced to Montville, New Jersey before four alleged heroin traffickers were arrested Sunday after a months-long investigation.

Some 154 pounds of heroin with a street value of around $50 million, in addition to $2 million in cash and a loaded gun were seized in the Fieldston section of the Bronx on Sunday, according to the Drug Enforcement Agency. With wiretaps in place, law enforcement officials learned a "sizeable shipment" of heroin was coming to a New York City apartment once a month through a Mexican drug cartel named the Sinaloa Cartel, the DEA said. As a result, heroin was being supplied to the users in all five boroughs of New York City, Connecticut, Massachusetts, Pennsylvania, and Rhode Island.

On Saturday, May 16, authorities followed two vehicles from the Bronx location to an industrial parking lot in Montville, just off Route 287 in Morris County. The vehicles entered a section where tractor-trailers were parked and stayed for more than an hour before heading back to the city, the DEA said. After the vehicles returned to the Bronx, K9 units "hit" on narcotics being inside the vehicle, the DEA said. The following morning, agents saw Jose Mercedes, 47, arrive in a different vehicle and was stopped for questioning. Agents then found "several large bags containing a powdery substance" inside the car, which tested positive for heroin, the DEA said.

As the search was taking place, Yenci Cruz Francisco, 20, was seen leaving the Bronx apartment and entering the Chevy Suburban that was followed to New Jersey the previous day. Agents stopped him and searched the vehicle, finding 70 individual one-kilogram packages of heroin labeled "Rolex" along with $24,000 in cash, the DEA said.

A subsequent search of the Bronx apartment yielded $2 million, which was stashed under the floorboards, the DEA said. A second apartment in the Bronx associated with the cartel yielded a .380 caliber firearm.

The 70 packages of heroin has a street value of $50 million, the DEA said, but that is a conservative estimate. The shipment was so large, the DEA said, that it could have supplied a dose of heroin to "every man, woman and child in New York City."

Both Cruz Francisco and Mercedes were charged with criminal possession of a controlled dangerous substance in the first degree, criminal possession of a controlled dangerous substance in the third degree, and two counts of criminally using drug paraphernalia in the second degree. Both were jailed without bail.