Duc had years of experience in France, which had given him a good feel of how the French might be thinking and what their relations with Francophile members of the ARVN might resemble. He used this to concoct some plausible sounding and incriminating documents for Mậu.
With years of experience in France under his belt, Duc developed a keen understanding of French perspectives and anticipated how they might interact with fellow Francophiles within the ARVN. He then crafted plausible-sounding but damaging documents for Mậu.