At the risk of beating my conspiracy-prone mindset drum ($19.95 in the toy section at Walmart), I would bet that if one knew Mansur intimately the seeds were there before he went bonkers. I've mentioned David Ray Griffin, a truly renowned philosopher and theologian who went completely off the deep-end and became one of the leading 9/11 Truther spokesmen. I was astonished ... and yet, one of the reasons I had always enjoyed reading him is that he was very open to some of the psychical research in which I am interested. In other words, just a bit "out there" for someone with his academic standing. I don't think it takes a whole lot of fertilizer for the conspiracy-prone mindset to blossom into a full-tilt beanstalk (what?). This is particularly true when there are religious underpinnings. How many people become religious zealots and at least start pretending to believe things they would have previously thought were laughable?
I also love the tactic of Certain Conspiracy Wackos to distance themselves from other comspiracy wackos. This is what Jim Di Eugenio used to do and why he became apoplectic whenever I pointed out the close parallels between the UFO community and the JFKA community. "WHAT???" screeched Jimbo in righteous indignation. "Those UFO nuts are NUTS. My goofy kitchen sink of beliefs is SERIOUS RESEARCH!!!" Uh-huh. Certain Conspiracy Wackos right here on this thread, who likewise hold and promote other wacky beliefs ("You could look it up," as Casey Stengel used to say), insist they are somehow above the fray and able to look down with disdain on the those Wacky 9/11 Truthers. And on it goes.