Eight individuals were tried as conspirators: Mary Surratt, Lewis Powell. David Herold and George Atzerodt were hanged, Samuel Mudd, Samuel Arnold and Michael O'Laughlen g
…ot life and Edmund Spangler got six years. Additional information by Troy Cowan. Mary Surratt After her husband's death, Mary moved her family to Washington to get her son away from his dangerous involvement with the South. She wanted him to find safe, gainful, employment in Washington. Mary Surratt had no knowledge of Lincoln's assassination and was not involved. Lewis Powell Lewis attempted to kill Secretary of State Seward. (Seward was at home, in bed, convalescing from a carriage accident) David Herold David held Powell's horse while Lewis Powell went inside to kill Seward. Later he joined Booth in his escape. George Atzerodt George participated in the failed attempts to kidnap Lincoln. He participated on the condition that no one would be killed. Samuel Mudd Dr. Mudd helped Booth obtain a horse that was later used in the attempted killing of Seward. At the time of the sale, there were no plans to kill Seward, therefore, Dr. Mudd could have no knowledge of it. Dr. Mudd helped wounded or escaped Confederate soldiers get back south. The route that went through his farm was called the "Doctors Line". At the time Booth showed up at Mudd's house to get treatment for his injured leg, Dr. Mudd had no knowledge of Lincoln's assassination. Samuel Arnold and Michael O'Laughlen They participated in several failed attempts to kidnap Lincoln. After one of the failures, both men quit the group. They had no knowledge of Lincoln's assassination. Edmund Spangler Spangler installed the brace on the hallway door leading to the president's box at 12 o'clock on the day of the assassination. That brace would be used to keep others from entering the hall after the shot was fired. Spangler was also to turn out the house lights to help Lincoln's killer escape. When it was time to turn out the lights, Mr. Withers was sitting on the box that covered the valve, and Spangler could not turn off the lights. John Surratt John was traveling from Montreal to Washington when Lincoln was killed. He had no knowledge and did not participate in Lincoln's killing. The masterminds behind Lincoln's assassination got away with the crime. You should consider three people: Secretary of War, Edwin Stanton; Vice-president, Andrew Johnson; and founder of the Knights of the Golden Circle, Albert Pike. John St. Helen (aka John Wilkes Booth) said that Vice-president Johnson was working with him to kidnap Lincoln. At five p.m. on the afternoon of the killing, Booth went to Johnson and told him that he was giving up on kidnapping Lincoln and going back to acting. That is when Johnson talked Booth into killing Lincoln. That means Spangler installed the brace to the hallway door five hours before Booth and Johnson thought about killing Lincoln. Someone else was planning to kill Lincoln. Albert Pike was working with Booth to kidnap Lincoln on the morning of the assassination and had no plans to kill Lincoln at that time. When Spangler was installing the brace and preparing the theater for Lincoln's assassination, Booth, Johnson, and Pike had no plans to kill Lincoln. Another person was planning Lincoln's assassination; this writer believes it was Edwin Stanton. (MORE) 
