Four men, including an MTA subway conductor, were indicted for allegedly trafficking guns from South Carolina and Virginia and then transported on the Iron Pipeline, destined to be sold in Brooklyn, the borough's district attorney announced Thursday.

Montoun Hart, 49, of Brownsville, Brooklyn; Vernal Douglas, 49, of Flatlands, Brooklyn; Christopher Hodges, 31, of Walterboro, South Carolina; and Ira Jones, 42, of South Boston, Virginia were all indicted on various charges in a 139-count indictment with first-, second- and third-degree criminal sale of a firearm; second- and third-degree criminal possession of a weapon; fourth-degree conspiracy and related charges. Hart and Douglas were arraigned in Brooklyn Supreme Court. Hart has been remanded and bail was set at $750,000 for Douglas. Jones is awaiting extradition from Virginia. Hodges is being sought.

Attorney information for the accused was not immediately known.

The accused were indicted as a result of an investigation that spanned from October 2019 to October 2020, which began because of information obtained about an individual who was allegedly known as a gun merchant in Brownsville.

According to the district attorney's office, on Nov. 4, 2019, an undercover detective met Hart for the purpose of purchasing firearms. The undercover detective allegedly made six controlled firearm purchases from Hart from Nov. 4 to Nov. 19, 2019.

The undercover detective then facilitated a meeting between Hart and another undercover agent, who posed as an associate of the original undercover detective and who would purchase firearms on his behalf, according to the district attorney's office. Between Dec. 3, 2019 and Dec. 30, 2019, the second undercover agent allegedly made three controlled firearm purchases from Hart.

Over the course of the investigation, Hart allegedly conducted a total of 27 controlled gun buys with the undercover officers, selling a total of 44 firearms.

The investigation also found that all three of Hart’s alleged suppliers operate independently from one another, but their individual practices are similar: once a supplier obtained a firearm, he would tell Hart the make, model and price via telephone, and often send a photo of it. Hart then passed the details on to his customers, which in this case were undercover agents, and scheduled the sale. All of the alleged sales occurred within a block of Hart’s residence.

Douglas, who has been employed by the Metropolitan Transportation Authority as a subway conductor and lives in Brooklyn, also has an address in Williston, South Carolina, where he frequently travels. Douglas, who joined the MTA in 2017, allegedly obtained firearms during trips to South Carolina and has also asked his sources in South Carolina to send him firearms via the mail.

According to the MTA, Douglas is no longer in active service until further notice.

“The indicted conductor is not in active service and will remain out until further notice. The MTA has zero tolerance for conduct that facilitates crimes of violence, and fully cooperates with law enforcement investigations in such cases,” MTA spokesperson Tim Minton said in a statement to NBC 4 New York.

Additionally, Hodges, who lives in and operates out of Walterboro, South Carolina, allegedly accumulates firearms from a variety of sources and then travels up to New York via a Chinatown bus company to transfer the firearms to Hart.

Meanwhile, Jones, who lives and operates out of South Boston, Virginia, also allegedly travels up to New York with firearms for Hart to sell on the streets of Brooklyn.

Among the numerous firearms recovered are two assault weapon -- a German Sport Guns .22 caliber rifle and a Smith & Wesson 9mm semi-automatic pistol -- as well as a Ruger .44 caliber revolver, a Smith & Wesson .357 caliber revolver, a Springfield Armory 9mm pistol, a Taurus 9mm, a Glock .380 caliber, a Glock 9mm, and a Ruger P89 9mm pistol.

“This indictment is part of our multi-pronged approach to stem the surge in gun violence that we have seen in Brooklyn and throughout the entire city this year," Brooklyn District Attorney Eric Gonzalez said in a statement. "We are determined to work with the Police Department to focus specifically on the drivers of crime, including those responsible for the proliferation of firearms by bringing them to streets of Brooklyn.”

Meanwhile, Chief of Detectives Rodney Harrison shared similar sentiments, saying in a statement: “This indictment is another example of how the NYPD and our law-enforcement partners remain focused on eliminating illegal guns from the streets of New York City. Bringing gun traffickers to justice is dangerous work, but the NYPD remains committed to protecting New York City communities and keeping people safe.”