MIAMI (AP) — A former American diplomat who served as United States (US) ambassador to Bolivia has been arrested in a long-running FBI counterintelligence investigation, accused of secretly serving as an agent of Cuba’s government, The Associated Press (AP) has learned.

Manuel Rocha, 73, was arrested in Miami on Friday on a criminal complaint and more details about the case are expected to be made public at a court appearance Monday, said two people who spoke to the AP on condition of anonymity because they were not authorised to discuss an ongoing federal investigation.

One of the people said the Justice Department case accuses Rocha of working to promote the Cuban government’s interests. Federal law requires people doing the political bidding of a foreign government or entity inside the US to register with the Justice Department, which in recent years has stepped up its criminal enforcement of illicit foreign lobbying.

The Justice Department declined to comment. It was not immediately clear if Rocha had a lawyer and a law firm where he previously worked said it was not representing him. His wife hung up when contacted by the AP.

Rocha’s 25-year diplomatic career was spent under both Democratic and Republican administrations, much of it in Latin America during the Cold War, a period of sometimes heavy-handed US political and military policies. His diplomatic postings included a stint at the US Interests Section in Cuba during a time when the US lacked full diplomatic relations with Fidel Castro’s communist government.

Born in Colombia, Rocha was raised in a working-class home in New York City and went on to obtain a succession of liberal arts degrees from Yale, Harvard and Georgetown before joining the foreign service in 1981.

He was the top US diplomat in Argentina between 1997 and 2000 as a decade-long currency stabilisation program backed by Washington was unravelling under the weight of huge foreign debt and stagnant growth, triggering a political crisis that would see the South American country cycle through five presidents in two weeks.

At his next post as ambassador to Bolivia, he intervened directly into the 2002 presidential race, warning weeks ahead of the vote that the US would cut off assistance to the poor South American country if it were to elect former coca grower Evo Morales.

“I want to remind the Bolivian electorate that if they vote for those who want Bolivia to return to exporting cocaine, that will seriously jeopardise any future aid to Bolivia from the United States,″ Rocha said in a speech that was widely interpreted as a an attempt to sustain US dominance in the region.

The gambit angered Bolivians and gave Morales a last-minute boost. When he was finally elected three years later, the leftist leader expelled Rocha’s successor as chief of the diplomatic mission for inciting “civil war.”

Rocha also served in Italy, Honduras, Mexico and the Dominican Republic, and worked as a Latin America expert for the National Security Council.

Rocha’s wife, Karla Wittkop Rocha, would not comment when contacted by the AP.

“I don’t need to talk to you,” she said before hanging up.

Following his retirement from the State Department, Rocha began a second career in business, serving as the president of a gold mine in the Dominican Republic partly owned by Canada’s Barrick Gold.

More recently, he held senior roles at XCoal, a Pennsylvania-based coal exporter; Clover Leaf Capital, a company formed to facilitate mergers in the cannabis industry; law firm Foley & Lardner and Spanish public relations firms Llorente & Cuenca.

“Our firm remains committed to transparency and will closely monitor the situation, cooperating fully with the authorities if any information becomes available to us,” Dario Alvarez, CEO of Llorente & Cuenca’s US operations, said in an email.

XCoal and Clover Leaf Capital did not immediately respond to a request for comment. Foley & Lardner said Rocha left the law firm in August.