From the article above.
Motivated by the persecution of his wife’s parents under Joseph Stalin and disappointed in the communist government, Tolkachev established ties to the U.S. Central Intelligence Agency in Moscow and, beginning in 1979, began transferring huge volumes of highly classified and extremely sensitive data about the most important avionics, radars and weapons installed in Soviet-made combat aircraft.
He paid the ultimate price in the end. What about his wife and other family members? Espionage is a high risk venture.