I was wrong. I have heard of Frank Snepp, he was one of those who
interrogated Nguyen Van Tai, the highest North Vietnamese insurgent
captured, and who was based in Saigon. For years they tortured the guy,
all the usual stuff; but he never revealed his secrets, they never broke
him. I spent some time in a previous posting a few years back on
Cryptome Mailing list on his case.
It would be interesting to know who the American spy was in the North
Vietnamese Central Committee and who fed the US with accurate
information on what the North Vietnamese were up to....