Don Thomas addresses a public forum to answer questions about the conspiracy to destroy Booths diary confession. Eight days after shooting Lincoln, Booth . Two years after the conspiracy trial ended Congress discovered that the military prosecution suppressed evidence written by John Wilkes Booth during his . Author of the Reason Lincoln had to Die. . During the Judiciary investigation into Booths diary, the detective who recovered the diary from Booths body inadvertently exposed the reason why the military .