A former CIA officer has been arrested for keeping details of US agents, safe houses and other secrets years after retiring from the agency and moving to Hong Kong.

The former intelligence officer, Jerry Chun Shing Lee, was detained at JFK airport on Monday, more than five years after FBI agents discovered he had kept a small address book and pocket calendar containing secret operational notes from his time at the CIA, about “asset meetings, operational meeting locations, operational phone numbers, true names of assets and covert facilities” according to court documents.

Lee, a 53 year-old naturalised US citizen who left the CIA in 2007, made an initial appearance in a New York federal court on Tuesday. He was charged with the unlawful retention of national defence information. He is due to appear at another court in northern Virginia, where the CIA is located.

The New York Times and the Washington Post reported that Lee is suspected of leaking the names of US agents to the Chinese authorities, in one of the deadliest intelligence setbacks for the CIA since the cold war. Between 2010 and 2012, the Chinese killed or imprisoned more than a dozen US sources in China, the New York Times reported last year.

Lee was not charged with crimes related to the breach or spying for a foreign government. It is unclear why Lee was not arrested when his notebooks were first found by FBI agents during a search of his luggage during trips to Hawaii and Virginia in 2012, five years after leaving the CIA. Nor is it clear why he travelled back to the US in 2012 and on Monday, knowing he was under suspicion for leaks.

The Department of Justice said Lee grew up in the US and served in the US army before joining the CIA as a case officer in 1994.

He served in unnamed overseas locations and left the agency in 2007. He was most recently reported to be have been employed in Hong Kong at an auction house.

Officials did not say why it took so long to bring charges against Lee, or whether he had leaked any materials to foreign countries. Former intelligence officials told the New York Times that the FBI managed to persuade Lee to travel to the US under a false pretext, and interviewed several times in 2013.

A CIA spokesman declined to comment on the case on Tuesday, citing Lee’s ongoing prosecution.

Asked about the case at a regular press briefing in Beijing on Wednesday, Chinese foreign ministry spokesman Lu Kang said: “I’m not aware of the information you’ve mentioned.”