Here is an interesting link re: Kerry and the FBI files.
"[redacted] that on April four, one nnie seven two, a representive of the North Vietanese Government at the Paris Peace talks telephoned the 'movement' in the United States to be ready to take action, presumably demostrations, to counter expected escalation of bombing by American air forces in South Vietnam as a result of the increased military action of North Vietnamese forces in Quang Tri Province, South Vietnam."
http://www.freerepublic.com/focus/f-news/1201299/posts
Sorry it took me so long to respond. That's DYNAMITE. I can certainly look it up--but was Kerry still part of the leadership at that time? And--I don't recall Nixon's resumption of heavy bombing 'til (or even the hint of it) before November '72. Of course, it began in December. How could the Vietnamese have suspected BEFORE April 1972? Not even Nixon was confident of re-election. Absolutely amazing how good their sources were . . .