A former Swiss banker has been sentenced to 10 years in prison for his role laundering $1.2 billion stolen from Venezuela's state oil company in a high-profile case implicating President Nicolas Maduro's stepsons.

Matthias Krull is cooperating with prosecutors, and the judge in Monday's hearing said his sentence could be reduced. The former Julius Baer banker will remain free on bail until April 29. Since his arrest in July at Miami's international airport, he has pleaded to one count of money laundering and agreed to forfeit $600,000, his take from the scheme that sought to siphon off funds from state-run PDVSA through a mix of fraudulent contracts and black market bolivar loans.

The investigation, the biggest money-laundering case ever lodged against Venezuelan officials and their associates, is part of a vast, multiyear effort by U.S. prosecutors to close the net on Maduro, who has largely dodged the allegations of corruption that have resulted in charges against several senior officials.

In previously unsealed court documents, Krull admitted that he plotted with men identified only as “Los Chamos,” Venezuelan slang for “the kids,” to hide a $200 million slice of the embezzled funds by investing it in luxury Miami real estate.

Los Chamos actually are Yoswal, Yosser and Walter Flores, the children of First Lady Cilia Flores from a previous relationship, according to two Americans with direct knowledge of the case who discussed it with the AP. They spoke on the condition of anonymity because of the sensitive nature of the allegations.

In court papers. Krull also was referred to as the “personal banker” for “Conspirator 7,” who is described as the owner of a Venezuelan TV network and billionaire member of the so-called boliburgues elites that made fortunes under the Bolivarian revolution started by the late Hugo Chavez. The two people familiar with the case said Conspirator 7 is Raul Gorrin, who became president of Globovision shortly after he and others purchased the popular network in 2013 and softened its anti-government coverage.

Neither Gorrin nor Maduro's stepsons have been charged in the case.

Other indicted co-conspirators include former PDVSA officials, including Abraham Ortega, a former executive finance director at the company, who has also turned himself in and is expected to plead guilty to the same charges as Krull in a hearing scheduled for later this week.

A lawyer for Gorrin did not immediately reply to a request for comment. No contact information was available for Maduro's stepsons.

Krull was born in Germany but moved as a young boy to Caracas, where his father worked as a pastor for the German Lutheran community. His parents were later divorced and he finished high school with his father's family in Mexico and then moved to Switzerland before joining Julius Baer and relocating to Panama.

His father, now retired, said his son had committed a “big mistake,” but was sure that he regretted his actions and would not repeat them, according to a letter he wrote to the judge requesting leniency. Others described him as a generous member of a patchwork family spread across the globe. His 70-year-old mother, who lives in Wuppertal, Germany, said she was “praying to God I will see him again in my lifetime.”

Prosecutors say the embezzled funds involved in Krull's plea deal were generated by a 2014 loan that the oil company obtained in local bolivars from a Venezuelan shell company. Two months later, they say, PDVSA repaid the loan to a Hong Kong-based shell company called Eaton Global, which had taken over the loan, at an official exchange rate well above the black market rate used by the majority of Venezuelans when buying hard currency.

Prosecutors say that allowed Eaton, which they contend was controlled by the conspirators, to collect some $582 million from PDVSA, almost 15 times the original loan amount, according to Krull's plea and worksheets obtained by investigators.

One of the first lady's nephews was serving as PDVSA's vice president of finance at the time the loan was repaid to Eaton.

Two of her other nephews were found guilty in New York of conspiring to smuggle cocaine into the U.S. and in 2016 were sentenced to 18 years in prison.