Philip J. Klass.

Klass was the best-known skeptical UFO investigator. He demonstrated that the Truman signature was a photocopy lifted from a genuine 1947 memo, showed the documents' anachronistic date format matched Moore's personal letters, and argued Robert Cutler was abroad on the Cutler-Twining date. He named Moore the likely forger but rejected the intelligence-disinformation theory as too crude to fool foreign services, favoring a straightforward hoax.