Read this book, "The Judicial Hanging of Mary E. Surratt", first published in 1895. http://www.encyclopedia.com/doc/1E1-Surratt.html
There is a legal principle in this country that requires the prosecution to deliver exculpatory evidence to the defendant's lawyer. The first hanging of an American woman was a miscarriage, a small footnote to the War to End Southern Independence. The conspirators, hung with her, pleaded for her release and vowed she had nothing to do with the assasination. Her last words, "please don't let me fall".
The prosecution, headed by Judge Advocate General Joseph Holt , never established that Mary Surratt even knew (although she might have known) of the abduction plot, and it now seems certain that she was not a party to the assassination plans. Booth's diary and other evidence that might have cast doubt on the prosecution's case were suppressed by the government, and it is generally believed that some of the testimony against Mary Surratt was false.