A businessman who was a close ally of the Venezuelan president, Nicolás Maduro, was secretly signed up by the Drug Enforcement Administration as a cooperating source in 2018 and provided agents with information about bribes he paid to Venezuelan officials, according to a US court filing unsealed on Wednesday.

Alex Saab agreed to be an “active law enforcement source” for the DEA and forfeited nearly $10m of his fortune as part of his cooperation agreement with the US, which included several meetings with US law enforcement officials in his native Colombia and Europe.

However, he was deactivated as a source after failing to meet a 30 May 2019 deadline to surrender himself.

Two months later, he was sanctioned by the Trump administration and indicted in Miami federal court on charges of siphoning millions from state contracts to build affordable housing for Venezuela’s socialist government.

A lawyer for Saab, David Rivkin, said in a statement that Saab only met with US law enforcement officials to explain that his companies had done nothing wrong, adding that Venezuela was fully aware of his engagement with those officials.

But the news could be an embarrassment to Maduro’s government, which has championed Saab as a special envoy who helped Venezuela’s government conduct business deals under the radar of US sanctions meant to force the ruling Socialist party from power.

Saab was indicted in 2019 and arrested in 2020 while he was refueling his plane in the west African island nation of Cape Verde, which last year approved his extradition to the United States – a move Maduro’s government described as a kidnapping.

US prosecutors say Saab, a Colombia-born businessman, siphoned about $350m out of Venezuela via the United States as part of a scheme that involved bribing Venezuelan government officials for fake import documents to secure dollar payments at a favorable exchange rate.

Saab has pleaded not guilty to the charge against him.

“The DEA and government counsel specifically advised [Saab] in April and May 2019 that his failure to surrender to US authorities would result in him being charged in the southern district of Florida,” reads the filing, originally submitted on 23 February 2021.

Venezuela’s information ministry did not immediately reply to a request for comment.

Prosecutors had asked that the filing remain sealed, arguing that Saab’s family could face harm if the information were made available to Maduro’s government. Judge Robert Scola on Wednesday ordered that the filing be unsealed.

Rivkin, Saab’s attorney, said in the statement that the release of the filing “is no more than an attempt to harm the interests of the Bolivarian Republic of Venezuela.

“Alex Saab remains a loyal citizen and diplomat of the Bolivarian Republic of Venezuela and will never do anything to harm the interests of the country and people that have given him so much,” Rivkin wrote.

Maduro’s allies have characterized Washington’s pursuit of Saab as part of an “economic war” on Venezuela being waged by the US government. They say Saab had been granted Venezuelan citizenship and had been named a diplomat to negotiate aid and fuel shipments from Iran.