 In October , Booth made an unexplained trip to Montreal , which was then a well @-@ known center of clandestine Confederate activity . He spent ten days in the city , staying for a time at St. Lawrence Hall , a rendezvous for the Confederate Secret Service , and meeting several Confederate agents there . No conclusive proof has linked Booth 's kidnapping or assassination plots to a conspiracy involving the leadership of the Confederate government , although historians such as David Herbert Donald have said , " It is clear that , at least at the lower levels of the Southern secret service , the abduction of the Union President was under consideration . " Historian Thomas Goodrich concluded that Booth entered the Confederate Secret Service as a spy and courier . Other writers exploring possible connections between Booth 's planning and Confederate agents include Nathan Miller 's Spying For America and William Tidwell 's Come Retribution : the Confederate Secret Service and the Assassination of Lincoln . 
