In Washington's Old Penitentiary, the taking of evidence in the Lincoln conspiracy trial concludes

The nine officers of the Commission to try the accused plotters - seven generals and two colonels - had been named on May 6, 1865. Preliminaries complete, the taking of testimony had began in earnest in the hearing room at the Old Washington Penitentiary on May 12, 1865 and continued until June 14, 1865.  After final arguments, deliberation began June 29, 1865, and sentences pronounced on July 6, 1865.  (By John Osborne) 
Source Citation
Clara E. Laughlin, The Death of Lincoln: The Story of Booth's Plot, His Deed and the Penalty (New York: Doubleday, Page and Company, 1909), 190-191. 
How to Cite This Page: "In Washington's Old Penitentiary, the taking of evidence in the Lincoln conspiracy trial concludes," House Divided: The Civil War Research Engine at Dickinson College, http://hd.housedivided.dickinson.edu/node/43975.