The former agent, Jose Irizarry, abruptly quit his position at the D.E.A. and is suspected of passing information to Colombian drug traffickers, according to BuzzFeed News, which first reported the investigation.
“The matter remains ongoing within the D.E.A. disciplinary system, and we cannot comment at this time,” said Melvin Patterson, an agency spokesman.
The allegations against Mr. Irizarry could make it more difficult for United States law enforcement officials to earn the trust of confidential informants in the shadowy world of drug trafficking. In some Latin American countries like Colombia, where cartels rule with force, cooperating with law enforcement almost certainly spells a death sentence.
Informants are a critical tool for United States law enforcement officials working to untangle transnational drug trafficking. But their ability to protect those informants has come under scrutiny in recent years.