A former CIA officer charged earlier this year with retaining classified information is now accused of espionage, a far more serious crime that could put the suspected Chinese mole in prison for decades.

Jerry Chun Shing Lee, 53, was indicted Tuesday in federal court in Alexandria, Virginia. He has been held in Alexandria’s jail without bond since January.

Prosecutors allege that in 2010, three years after Lee left his CIA job, two Chinese intelligence officials offered to pay him for information. Prosecutors say Lee prepared documents in response to the Chinese requests, made unexplained cash deposits, and lied in interviews about his travel to China and actions there.

Many in the CIA have long believed that Lee played a role in the exposure and deaths of multiple agency sources in China, according to current and former officials. But officials were divided over whether there was enough evidence to convict him, and even if there was, whether it was worth revealing sensitive spycraft to do so. Tuesday’s indictment did not address any effects of Lee’s alleged espionage.

Lee continued to maintain his innocence.

“I don’t think there’s any evidence that Mr. Lee was a spy for China, and we look forward to proving that at trial,” defense attorney Ed MacMahon said.

Lee was arrested in January upon landing at an airport in New York and accused of keeping notebooks full of detailed information about undercover agents and assets after leaving the CIA.

Agents also found a thumb drive with a document classified as secret on it. According to prosecutors, Lee admitted in interviews that he had prepared that document at the Chinese intelligence officials’ directive.

His return was a surprise, according to government officials. Law enforcement had been trying without success to get him back to the United States from Hong Kong for several years.

Lee joined the CIA in 1994 and left in 2007. In late 2011, a worried FBI informant in China told his American handlers that everyone he knew who was helping the U.S. government was being exposed and forced to work for the Chinese - or in some cases killed.

Lee became a suspect. In 2012, law enforcement officials say, he was lured from China to Virginia with a job offer. While he was in the United States, FBI agents searched his hotel rooms and found in his luggage a pair of small notebooks containing handwritten notes, including the real names and phone numbers of CIA assets and covert employees, as well as notes from meetings with those assets and the locations of covert facilities in China, according to court documents.

The following year Lee was interviewed five times by FBI agents, according to prosecutors. At no point did he reveal the existence of the notebooks.

In June 2013, he moved back to Hong Kong. At the time of his arrest he was working in security there for the auction house Christie’s.

Lee served in the U.S. Army from 1982 to 1986, according to court records. After that he went to Hawaii Pacific University, where he graduated in 1992 with a bachelor’s degree in international business management and in 1993 got a master’s degree in human resource management.

“The United States will hold accountable those who conspire to compromise our national security,” Tracy Doherty-McCormick, acting U.S. attorney for the Eastern District of Virginia, said in a statement.

If convicted, Lee could spend the rest of his life behind bars.