(Reuters) - The assistant to a billionaire real estate developer from Macau accused of engaging in a scheme to pay bribes to a former United Nations General Assembly president is in plea talks, his lawyer said on Tuesday.

FILE PHOTO: Jeff Yin, an associate of Ng Lap Seng who heads Sun Kian Ip Group, exits the Manhattan U.S. District Courthouse in New York, December 10, 2015. REUTERS/Brendan McDermid

The negotiations involving Jeff Yin, who was arrested along with billionaire Ng Lap Seng in 2015, were disclosed in a letter filed in Manhattan federal court by his attorney, who said prosecutors had extended him a plea offer.

The lawyer, Sabrina Shroff, sought to extend court deadlines so that Yin, 31, could consider the plea offer, which “is complex and involves civil tax assessments and liabilities,” according to her letter.

The plea talks come ahead of a jury trial scheduled for May 15, in which Yin and his boss could face substantial prison time if convicted.

It was unclear what charges Yin would have to plead guilty to if he accepted the offer. He had faced bribery, money laundering and tax-related charges, and was also accused of violating the U.S. Foreign Corrupt Practices Act.

Shroff declined comment. The U.S. Attorney’s Office in Manhattan, which is pursuing the case, also declined comment.

Ng, who was once linked to a campaign fundraising investigation during former U.S. President Bill Clinton’s administration, is one of seven individuals charged since October 2015 in the U.N.-related probe.

Prosecutors accuse Ng and Yin of paying more than $500,000 in bribes to John Ashe, a former U.N. ambassador from Antigua and Barbuda who served as General Assembly president from 2013 to 2014. Ashe died in June awaiting trial.

The indictment said Ng and Yin also paid bribes to Francis Lorenzo, a then-deputy U.N. ambassador from the Dominican Republic who pleaded guilty in March 2016 to bribery and money laundering charges as part of a deal to cooperate in the probe.

The main goal of the bribes, according to the indictment, was to have both ambassadors take steps to help obtain United Nations’ support for a multibillion-dollar U.N.-backed conference center in Macau that Sun Kian Ip Group would develop.

Yin, a U.S. citizen who currently lives in California, also faces charges for taking steps to evade paying income taxes and helping Lorenzo conceal portions of his income from U.S. tax authorities.

Ng, the founder of Macau-based real estate developer Sun Kian Ip Group, has denied wrongdoing. A lawyer for Ng declined to comment.