In March 1956, shortly after Mankiewicz bought the film rights to The Quiet American, Lansdale wrote to the director from his Saigon operations headquarters and, showing his skills as a former advertising executive, explained how to turn the novel into an assault on Greene and an advertisement for Diem. Although Lansdale acknowledged that Trinh Minh Thé had done the bombing and claimed credit for it in a radio broadcast, he assured Mankiewicz that no "more than one or two Vietnamese now alive know the real truth of the matter, and they certainly aren't going to tell it to anyone," so he should "just go ahead and let it be finally revealed that the Communists did it after all, even to faking the radio broadcast.