Jose Ismael Irizarry was sent to Cartagena to investigate money laundering by Colombia’s notoriously violent drug cartels. But instead of using his stable of confidential informants to bring down the gangs, the authorities said, Mr. Irizarry worked with a Colombian drug trafficker to launder money seized from undercover drug operations and used the cash to buy a Tiffany diamond ring, a $135,000 Land Rover and a home in Cartagena.

On Friday, Mr. Irizarry, a former special agent with the Drug Enforcement Administration who had worked in Miami, Cartagena and Washington until he resigned in 2018, was arrested along with his wife, Nathalia Gomez-Irizarry, near their home in San Juan, P.R.

Mr. Irizarry, 46, was charged with conspiracy to launder money, honest services wire fraud, bank fraud, conspiracy to commit bank fraud, conspiracy to commit identity theft and aggravated identity theft. Ms. Gomez-Irizarry, 36, was charged with conspiracy to launder money.

Both were released on bond and are due back in court on Wednesday. José Luis Novas-Debién, a lawyer for the couple, did not immediately respond to messages on Saturday.