Months after a low-level aide in the administration of Gov. Andrew M. Cuomo returned from a visit to China in 2019, she got a curious inquiry from federal investigators.

The F.B.I. wanted to know about the nature of the trip that the aide, Linda Sun, had taken.

The interaction in 2020 was one of the first known instances of governmental interest in Ms. Sun’s activities, according to a federal indictment unsealed on Tuesday. But it was not the last.

In February 2023, Ms. Sun was interviewed by the state’s Office of the Inspector General about her unauthorized procurement of official proclamations from the governor’s office, according to a federal indictment unsealed on Tuesday.

And when Ms. Sun was fired by Gov. Kathy Hochul’s administration weeks later, state officials’ suspicions surrounding Ms. Sun were “reported immediately to law enforcement,” the governor said on Wednesday.

Before her dismissal, even as questions were repeatedly raised, Ms. Sun continued to use her positions in state government to benefit the People’s Republic of China and its Communist Party in exchange for millions of dollars in benefits, according to prosecutors with the U.S. attorney’s office in Brooklyn.

In a 65-page indictment, prosecutors laid out a yearslong scheme in which Ms. Sun blocked Taiwanese officials from having access to the governor’s office, eliminated references to Taiwan and Uyghurs from state communications and quashed meetings with Taiwanese officials, all in an effort to bolster Chinese government positions.