The Union Army: A History of Military Affairs in the Loyal Staes 1861-65: Records of the Regiments in the Union Army; Cyclopedia of Battles; Memoirs of Commander and Soldiers, Vol. III (New Jersey, Indiana, Illinois and Michigan, published in 1908. Available online at https://books.google.com/books?id=XVNLAAAAYAAJ <https://books.google.com/books?id=XVNLAAAAYAAJ&pg=PA104&dq=%22horace+heffre n%22&hl=en&sa=X&ei=5c5cVdveNIbzsAX2v4CwCQ&ved=0CCYQ6AEwAjgK#v=onepage&q=%22h orace%20heffren%22&f=false> &pg=PA104&dq=%22horace+heffren%22&hl=en&sa=X&ei=5c5cVdveNIbzsAX2v4CwCQ&ved=0 CCYQ6AEwAjgK#v=onepage&q=%22horace%20heffren%22&f=false. Horace Heffren, who was tried on conspiracy charge in 1864, "was released from arrest and discharged, and thereupon became an important witness for the prosecution. The court found (William A.) Bowles, (Lambdin P.) Milligan, (Stephen) Horsey and (Andrew) Humphreys guilty (of the charge of conspiracy to overthrow the government) and sentenced the first three to death. Humphreys was condemned to imprisonment for life." After the day was fixed for their execution and preparations were commenced, President Johnson commuted their sentence to imprisonment for life at hard labor in the Ohio penitentiary. Later yet the president directed the discharge of the prisoners.