Prosecutors claim Mr Ma met with at least five officers of China's Ministry of State Security 12 years after he left the agency. The meetings took place in a hotel room in Hong Kong, during which he "disclosed a substantial amount of highly classified national defence information" to the Chinese.
The information included details of the CIA's internal organisation, identities of CIA officers and their human intelligence assets and the agency's methods for covert communication.
After leaving the CIA, Mr Ma worked as a Chinese linguist at the FBI's Honolulu field office. While working there he allegedly used his position to copy documents and photographs detailing guided missile systems and other classified information. He then allegedly handed that information over to his Chinese handlers.
Once the FBI caught on to his actions, an undercover agent arranged to meet with Mr Ma, posing as a Chinese government official. The operative claimed he was investigating "how Ma had been treated, including the amount he had been compensated," according to court documents.
In a video captured by the FBI, Mr Ma is seen counting $2,000 in cash given to him by the undercover agent. The agent said the payment was to acknowledge his work on behalf of China.
Investigators claim Mr Ma said he "wanted 'the motherland' to succeed." Mr Ma was born in Hong Kong. During the meeting, Mr Ma allegedly admitted that he had provided the Chinese with classified information.
One of Mr Ma's relatives, an 85-year-old man who also formerly worked for the CIA, was also found to be spying for China, but was not charged due to his advanced age and "debilitating cognitive disease."
Last year, another former CIA officer, Jerry Chun Shing Lee, was sentenced to 19 years in prison after he pleaded guilty to conspiring with Chinese intelligence agents.
According to NBC News, the information Mr Lee gave the Chinese compromised the CIA's methods of covert communication and contributed to the deaths of Chinese intelligence agents working for the US.
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