A former CIA officer apprehended in January at New York's John F. Kennedy airport is now facing charges of conspiracy to commit espionage on behalf of China.
The charges on Tuesday came years after FBI agents turned up notebooks containing confidential information in a search of his hotel room.
Jerry Chun Shing Lee, 53, is a naturalized US citizen, who had a top-secret clearance, working as a field agent for the agency between 1994 and 2007.
He was living in Hong Kong when he was arrested after apparently been the target of an FBI investigation since 2012, the time when agents found some handwritten notes while searching a Honolulu hotel room.
The notes were about "asset meeting, operational meeting locations, operational phone numbers, true names of assets, and covert facilities" pertaining to China, according to a court affidavit.
The New York Times has said in a report that the classified information is believed to have been used by Beijing to dismantle US spy operations and identify informants inside China.
The charges also included two counts of illegally keeping documents pertaining to US national defense.
"The allegations in this case are troubling," said Tracy Doherty-McCormick, acting US attorney for the Eastern District of Virginia. "Conspiring with foreign agents poses a real and serious threat toward our national security."
Lee's attorney, Edward MacMahon, has denied the charges. After his client’s initial court appearance in February, MacMahon said, "Mr. Lee is not a Chinese spy," noting, "He is a loyal American who loves his country."
If convicted, Lee would face a maximum of life in prison.