The Justice Department defended the Drug Enforcement Administration’s controversial money laundering stings, pointing out they have been used since 1984 to successfully bring down dozens of major gangsters.

Assistant Attorney General for Legislative Affairs Ronald Weich described the DEA’s operations in a letter to Rep. Darrell Issa of California, details of which were published Friday by the Houston Chronicle.

Weich said that Congress gave authority for the DEA to set up bank accounts to entrap the money of narcotics traffickers and transfer money to the gangsters in 1984 under President Ronald Reagan, who beefed up the war on drugs.

The stings, help “to identify how criminal organizations move their money, where they keep their assets and, most important, who their leaders are,” Weich wrote, according to the Chronicle.

Attention was brought to the money laundering stings following a Sunday story in the New York Times, describing how they were being used to launder the money of Mexican cartels.

Rep. Issa subsequently opened a probe into them.

The DEA also issued a new release on Tuesday defending its work with Mexico on such stings.

“The Drug Enforcement Administration has been working collaboratively with the Mexican government to fight money laundering for years,” the release said. “As a result of this cooperation, DEA has seized illicit transnational criminal organization money all around the world.”

The money laundering revelations are the latest in a series of scandals over the tactics of American agents fighting Mexican cartels.

(Read about America’s Shadow War on Drugs)

