From the acknowledgments section of Don’t Shoot That Boy!: Abraham Lincoln and Military Justice: “As always, any errors, omissions, or ill-founded opinions are the sole responsibility of the author.” [You said it.]
Update from the Washington Post: In an interview Lowry claims that Archive officials pressured him to confess to the document tampering.
Washington, DC…Archivist of the United States David S. Ferriero announced today that Thomas Lowry, a long-time Lincoln researcher from Woodbridge, VA, confessed on January 12, 2011, to altering an Abraham Lincoln Presidential pardon that is part of the permanent records of the U.S. National Archives. The pardon was for Patrick Murphy, a Civil War soldier in the Union Army who was court-martialed for desertion.