Jerry Chun Shing Lee, a former CIA officer, was arrested on charges of illegally possessing classified information.

Current and former intelligence officials believe that Lee may have passed information to Chinese intelligence officers, during a period when CIA assets in China were executed.

Officials also believe that that information may have been passed on to Russia.

A former CIA case officer who was arrested on Tuesday on a single count of illegally possessing classified information – real names and phone numbers of covert CIA sources, locations of covert facilities, and meeting locations – may have compromised US assets in Russia, according to current and former US officials cited in a NBC News report published Friday.

A secret task force involving the FBI and CIA suspected that 53-year-old ex-CIA officer, Jerry Chun Shing Lee, could have been spying for China, during a period when at least 20 CIA informants in China were executed. FBI agents were said to have received information that Lee, who left the CIA in 2007, was cooperating with Chinese intelligence officers while working in Hong Kong, according to sources cited in the report.

In 2012, agents reportedly searched his hotel room and discovered notebooks with the names and phone numbers of CIA sources.

US intelligence officials, who suspected that China had infiltrated their covert communications following the executions of their sources in the country, believed that Chinese intelligence officers shared the US’s method of covert communications with Russian intelligence officers during a joint training session. After the training session, Russian officers reportedly “came back saying we got good info on [covert communications],” a former official said to NBC News.

US assets in Russia reportedly began disappearing, prompting a change in operational procedures for communications.

The former officials noted that the information Lee possessed was not all-inclusive, and that not all of those who were sought by Chinese officials were linked to his notebook: “No single officer had access to all of them,” one official said to NBC News.

The former officials also noted that the CIA’s method for sharing messages with agents could have been easily accessed by the Chinese due to its simplicity: “All they had to do was get one agent’s laptop, and they could figure it out,” and official said.

Lee reportedly flew to back to the US in 2012 with his family on the promise of a job offer, which turned out to be a plan by authorities to lure him back to the US. Photographs taken of items in Lee’s hotel room at the time indicated he possessed a 49-page datebook and a 21-page address book filled with sensitive information.

Lee was arrested after flying into John F. Kennedy Airport from Hong Kong.

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