the keystone in the arch that some builders reject

The central premise of the 1977 book is that "traditional" historians have perpetuated a cover-up, originally orchestrated by Lincoln's Secretary of War Edwin M. Stanton(D) and some Radical Republican allies in 1865, by over-reliance on false documentation produced by Stanton and his conspirators. This was done, the book argues, to disguise the fact that Stanton, Union spy Lafayette C. Baker, Senator Benjamin F. Wade, Senator John Conness, other congressional Radical Republicans, and a group of Northern bankers and speculators were all involved in a plot to kidnap Lincoln. Lincoln was then intended to be hidden for a time while bogus articles of impeachment would be drafted to remove him as President. The primary motivations for this supposed plot would have been strong opposition to Lincoln's generous Reconstruction plans and the loss of profits due to Lincoln's restrictions on the cotton trade during the U.S. Civil War.  https://en.wikipedia.org/wiki/The_Lincoln_Conspiracy_(book)

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  Booth's diary was handed to Baker who later passed it onto Edwin M. Stanton.  

Lafayette Baker (shown) was rewarded for his success by being promoted to brigadier general and receiving a substantial portion of the $100,000 reward.

  Baker was dismissed as head of the secret service on 8th February, 1866.  Baker claimed that President Andrew Johnson had demanded his removal after he discovered that his agents were spying on him.  Baker admitted the charge but argued he was acting under instructions from the Secretary of war, Edwin M. Stanton....

  This information about Booth's diary resulted in Baker being called before a Congress committee looking into the assassination of Abraham Lincoln.  Edwin M. Stanton and the War Department was forced to hand over Booth's diary.  When shown the diary by the committee, Baker claimed that someone had "cut out eighteen leaves."  When called before the committee, Stanton denied being the person responsible for removing the pages.

  Speculation grew that the missing pages included the names of people who had financed the conspiracy against Abraham Lincoln.  It later transpired that John Wilkes Booth had received a large amount of money from a New York based firm to which Edwin M. Stanton had connections. 

  After his appearance before the Congress committee Baker became convinced that a secret cabal was intent of murdering him.  He was found dead at his home in Philadelphia on 3rd July, 1868. Officially Lafayette Baker died of meningitis but the authors of the book, The Lincoln Conspiracy (1977), claim that he was murdered by his brother-in-law, Walter Pollack, a detective at the War Department.  https://spartacus-educational.com/USAbaker.htm    (And in that book one can access the 18 missing diary pages.)

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  All right, detectives, try this:  Neff and Laf Baker and  
http://balance10.blogspot.com/2019/04/inside-abraham-lincoln-assassination.html