This primary source comes from the Records of the Office of the Chief Signal Officer.
National Archives Identifier:
530503Full Citation: Execution of the four persons condemned as conspirators, Mary Surratt, Lewis Powell, David Herold, and George Atzerodt; 07/07/1865; Civil War-Era Photographs, ca. 1921 - ca. 1921; Records of the Office of the Chief Signal Officer, Record Group 111; National Archives at College Park, College Park, MD. [Online Version, https://www.docsteach.org/documents/document/execution-of-the-four-persons-condemned-as-conspirators-mary-surratt-lewis-powell-david-herold-and-george-atzerodt, May 14, 2024]