The Nicholsons could each face sentences of up to 100 years in prison if convicted of all charges.
Harold Nicholson, who had held posts all over Asia and Eastern Europe, is the highest-ranking CIA officer to face espionage charges. He pleaded guilty to espionage charges in 1997, and a federal judge sentenced him to more than 23 years in prison.
He had begun selling U.S. secrets to Russia three years earlier, after the end of the Cold War era.
"I believed that I could work both for the CIA and for the Russian service at the same time. Russia was no longer the Communist government they had," he said in a 1997 prison interview aired on ABC News' Nightline. "They were not our number one enemy anymore. Our No. 1 enemy, in my opinion, is terrorism, and the Russians were working with us against terrorism."
According to court documents filed in the case, Nicholson, who started with the agency in 1980 and rose through the ranks to become a station chief in Romania and later an instructor in the classified CIA Special Training Center in Virginia, "held a 'Top Secret' security clearance, and had regular, frequent access to sensitive classified information."
In 1994, when he received his first $12,000 payment from the Russians, Harold Nicholson was working in Malaysia, where part of his job was to target Russian intelligence officers for recruitment.
In the two years of secret meetings with Russian contacts in Southeast Asia and Europe, he came under the scrutiny of those within the CIA.
After a series polygraph examinations and a CIA review of his personal records showed a pattern of international travel and unexplained deposits into his financial accounts, he was arrested at Dulles International Airport outside Washington, D.C.
By then, he had collected $300,000 from his Russian contacts. But in the 1997 interview, he downplayed the severity of his actions.
"No one was killed. No one was tortured and the only person that was arrested as a result of my action was me," he said.
But court documents indicate that Nicholson provided biographical and assignment information on CIA personnel to the SVRR, the successor organization to the USSR's infamous KGB.
Despite his conviction, Nicholson maintained that he was not the typical spy.
"I wasn't disaffected against my country. I had never shown any kind of criminal past or anything of this nature. I had a family who was patriotic. All of my friends were patriots," he said in 1997.
"There was nothing other than the fact that I just found myself in an untenable situation and I didn't know how to get out of it."