The son of an ex-CIA spy agreed to testify against his imprisoned father Thursday in a plea deal that could help him avoid jail time for taking money from Russian agents.

Nathaniel Nicholson pleaded guilty on Thursday to conspiracy to act as an agent of a foreign government and conspiracy to commit money laundering.

Jim Nicholson was the highest-ranking CIA official ever convicted of espionage when he pleaded guilty in 1997 to a conspiracy charge that sent him to prison for more than 23 years. He had been accused of selling information to the Russians about the CIA agents he trained and passing along other secrets.

Both Nicholsons were indicted in January on new charges of conspiracy, money laundering and acting as an agent of a foreign government. Jim Nicholson was accused of sending his son back to his Russian handlers from 2006 to 2008 to squeeze more money out of them.

Under the plea agreement, the 25-year-old Nicholson admitted taking money from the Russians and promised to testify, if required, against his father in the new case. In return, federal prosecutors have agreed to recommend a sentence that could result only in probation.

During a hearing before U.S. District Judge Anna Brown, Nathaniel Nicholson admitted traveling to San Francisco, Mexico City, Lima, Peru and Nicosia, Cyprus, to meet with agents of the Russian Federation on behalf of his father.