Jerry Chun Shing Lee, who left the agency in 2007, came under suspicion by FBI agents in 2012 after they discovered he had two notebooks that contained the real names of CIA operatives and covert facilities in China.
FBI officials had launched an investigation after a slew of CIA informants stationed in China were either killed or arrested in 2010, though it's unclear why Lee was listed as a person of interest prior to the 2012 search.
With little known about Lee's predicament, Coleen Rowley, a former FBI special agent, says suspicion tends to fall on people who are innocent.
Speaking to Radio Sputnik's Loud & Clear, Rowley said that "when you have you informants and sources inside a country disappearing or being killed, as apparently happened, there is immediate suspicion and often times that suspicion falls on people who are innocent."
Pointing out some of the obvious eyebrow-raising points of information, Rowley told show hosts Brian Becker and John Kiriakou that disappearances weren't noted by officials until 2010, roughly three years after Lee had already parted ways with the CIA.
"That's three or four years after he had resigned from the CIA," the former FBI agent said. "That alone is a little bit strange because usually when people resign or retire, after a while they no longer have any valuable information that they would be approached for."
"In my experience people who retire… who are going to use prior contacts they developed in their career… are some reasons why somebody could have notes from their job or even contacts of co-workers," she added. "It's fairly innocent reasons for having those which would have nothing to do with actually using those [contacts] to engage in espionage with a foreign power."
According to reports, Lee's Monday arrival at John F. Kennedy International Airport wasn't the first time that he had come back to US soil. In 2012, he returned from Hong Kong, where he was working at an auction house, to visit his family in Virginia. It was at this time that the FBI conducted its search and found the notebooks. After being questioned by officials several times, he chose to head back to Hong Kong.
However, if the charge against Lee stems from the 2012 search, Rowley suggests that the efforts by FBI officials "could have been a rush job when they found out [Lee] was going to come back to the states" as the statute of limitations might have been "running out."
"If [the charge against Lee] dates back to 2012 searches that the FBI conducted, [it shows that] they had to lure him back to the US to charge him at all," Rowley added.
The New York Times reported that Lee is being held in Brooklyn, New York, before being transferred to Virginia.