All I remembered is selling the guidance systems for MIRV'd ICBMs.
Here is a quick link... I can’t remember all the details..
Former Sandia and Los Alamos laboratory employee Peter Lee (no relation to Wen Ho Lee) gave top secret information on antisubmarine radar technology away to Chinese nuclear-weapons experts during a May 11 lecture at the Institute of Applied Physics and Computational Mathematics in Beijing, China. Lee pleaded guilty to filing a false statement about his 1997 trip to China and to giving classified laser data to Chinese scientists during an earlier trip to China in 1985.[16]
https://en.wikipedia.org/wiki/Timeline_of_the_Cox_Report_controversy
If I remember, it had something to do with submarine super quite propeller technology. I think