A former Central Intelligence Agency (CIA) officer was arrested on Monday at a US airport in connection to charges that he illegally retained highly-classified information, the US Justice Department says.

Key points: A former CIA officer was arrested on Monday

A former CIA officer was arrested on Monday According to the NYT, he was part of an FBI inquiry that started in 2012

According to the NYT, he was part of an FBI inquiry that started in 2012 He's accused of holding onto information identifying names and phone numbers of covert CIA employees

According to The New York Times, the arrest of Jerry Chun Shing Lee, 53, was part of an FBI inquiry that began in 2012, and followed the deaths of a number of CIA informants in China.

Who is he?

Jerry Chun Shing Lee is a US citizen who now lives in Hong Kong.

He used to maintain a top-secret clearance and began working for the CIA back in 1994.

The 53-year-old worked for the CIA until 2007 — according to an affidavit filed by an FBI agent — and previously served in the US Army from 1982 through to 1986.

He worked in a variety of overseas offices and was trained in surveillance detection, recruiting and handlings assets and handling classified material, among other things.

Mr Lee's security clearance was terminated in 2007 when he left government service.

What's he been accused of?

According to the affidavit, Mr Lee is accused of holding onto information identifying the names and phone numbers of covert CIA employees and locations of covert facilities.

In 2012, after Mr Lee left the CIA, he travelled from Hong Kong with his family to northern Virginia, where he lived from 2012 to 2013.

During this time, the FBI conducted a search of the family's hotel rooms during their stays at Hawaii and Virginia, finding two books containing classified information inside Mr Lee's luggage.

A CIA review of the information in the two small books — described in the affidavit as a datebook and an address book — found information at "secret" and "top secret" levels of classification.

At least one page contained top-secret information, "the disclosure of which could cause exceptionally grave damage to the national security of the United States," the agent said.

Mr Lee was arrested at John F Kennedy International Airport in New York on Monday.

Why has he been linked to an investigation into the deaths of CIA informants?

According to The New York Times, Mr Lee eventually became a suspect in a 2012 FBI investigation into how more than a dozen CIA informants were killed or imprisoned by the Chinese government.

Last year the newspaper reported that starting back in 2010, the Chinese government began systematically dismantling the CIA's spying operations in the country — killing or imprisoning more than a dozen sources over two years and crippling intelligence gathering there for years afterward.

The FBI reportedly began to suspect an insider had revealed sensitive information to the Chinese government.

That was a theory not initially supported by the CIA.

It was at some point during this investigation that Mr Lee became a prime suspect.

Mr Lee was interviewed by the FBI five separate times in 2013.

The court documents state he never disclosed he had the books.

He also met with former CIA colleagues around that time without returning the materials to the government, the Justice Department said.

Where is the case now?

Mr Lee made his first court appearance on Tuesday before a federal magistrate judge in Brooklyn.

The judge ordered Mr Lee held without bail.

The case is being prosecuted by the US Attorney's Office for the Eastern District of Virginia and he's being held in Brooklyn while awaiting transfer to Virginia — where the CIA is based.

A federal public defender who represented Mr Lee at Tuesday's hearing declined to comment.

Dean Boyd, a CIA spokesman, also declined comment on the case on Tuesday, citing Mr Lee's ongoing prosecution.

ABC/wires