The Justice Department unsealed charges Thursday stemming from what it says was a long-running conspiracy to launder billions of dollars from Malaysia’s investment development fund and announced that a former Goldman Sachs managing director has pleaded guilty in the case.

The indictment, filed in federal court in Brooklyn, centers on 1Malaysia Development Berhad, called 1MDB, which has been the focus of a long-running FBI investigation into how that money was moved and used.

Attorney General Jeff Sessions has called the 1MDB scandal “kleptocracy at its worst.”

One of the defendants, Ng Chong Hwa, 51, also known as Roger Ng, was arrested in Malaysia on Thursday on charges that he conspired to violate the Foreign Corrupt Practices Act, or FCPA, by circumventing accounting controls when he worked at Goldman under a partner at the firm, Tim Leissner.

Officials also revealed that Leissner, the former Southeast Asia chairman at the firm, has pleaded guilty to conspiring to launder money and conspiring to violate the FCPA. As part of his plea deal, Leissner has agreed to forfeit $43.7 million.

The indictment charges Ng and Low Taek Jho, also known as Jho Low, with a multibillion-dollar money-laundering conspiracy. Low has not been apprehended.

A spokesman for Low said he maintains that he is innocent and will be vindicated.

1MDB is a government-controlled fund that aimed to pursue economic-development projects for Malaysia. According to the Justice Department, billions of dollars were misappropriated and diverted from the fund, helped by bribes to government officials in Malaysia, an arrangement that authorities say also generated more business for Goldman Sachs.

Goldman Sachs said it was cooperating with the investigation.

The U.S. government charges that after one project was finalized in March 2013, more than $1 billion of diverted money was laundered, at Low’s direction, to bank accounts controlled by Low, Leissner and others, including 1MDB officials.