“James Ferguson, a witness for the prosecution, told of finding a letter floating in the water near Morehead City, North Carolina. The letter was in cipher. A translation of the letter, addressed to ‘John’ and dated April 15, was read into the court record.
“The letter makes coded references to killing Lincoln and others, including Generals Sherman and Grant. The letter appears to be a fabrication, but by whom and for what purpose is unclear.”
— From “The Lincoln Assassination Encyclopedia” by Edward Steers (2010)