The head of a New York-based foundation accused of participating in a scheme to bribe a former  United  Nations  General Assembly president is expected to plead guilty on Wednesday, a person familiar with the matter said.

Sheri Yan, who was Global Sustainability Foundation's chief executive, would become the second defendant to plead guilty in connection with an alleged conspiracy to bribe John Ashe, the former General Assembly president, the person said.

The expected plea by Yan, 57, comes less than a week after the former finance director at the foundation, Heidi Hong Piao, pleaded guilty and agreed to cooperate with authorities in their continuing investigation.

Both women were arrested in October by the Federal Bureau of Investigation as prosecutors unveiled charges over a multi-year scheme to pay more than $1.3 million in bribes to Ashe, who was also the U.N. ambassador from Antigua and Barbuda.

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A spokesman for Manhattan U.S. Attorney Preet Bharara declined comment. His office earlier Wednesday issued an alert that use language indicating that a plea was expected in the case, without specifying which defendant would plead guilty.

A lawyer for Yan, who faced charges including bribery and money laundering, did not immediately respond to a request for comment.

Prosecutors allege that Ashe, the U.N. General Assembly president from 2013 to 2014, accepted $1.3 million of bribes from Chinese businessmen to support their interests within the  United Nations  and Antigua.

Those bribes included over $800,000 from three businessmen that were arranged through Yan and Piao, prosecutors said.

Prosecutors have also charged Ng Lap Seng, a billionaire developer from the Chinese territory of Macau who allegedly paid $500,000 in bribes to Ashe through intermediaries.

Those intermediaries included Francis Lorenzo, a now-suspended deputy U.N. ambassador from the Dominican Republic, and Jeff Yin, Ng's assistant, prosecutors said.

Ashe, Lorenzo, Ng and Yin have pleaded not guilty.

Ashe, 61, has only been charged with tax fraud, as prosecutors have said diplomatic immunity may preclude any bribery charges. But prosecutors have said they were examining the issue and likely would bring further charges.