The city of Montreal, at the time, was leaning with sympathies towards both sides of the American conflict. The streets were filled with spies from both sides, exiled Confederates of high rank, sympathizers, arms dealers, Union detectives and saboteurs. Carroll became a fixture at the luxurious St. Lawrence Hall on St. James Street (now Saint Jacques Street) which was where the more affluent Confederates in Canada stayed such as Jacob Thompson, Clement Claiborne Clay, James Westcott, Moses Montrose Pallen, Luke P. Blackburn, Nathaniel Beverly Tucker and even John Wilkes Booth. Many plots were formed by the members of this group. After staying in Montreal for a time, Carroll sailed south and was captured off the coast of North Carolina. He was placed in prison in Fortress Monroe, and was quickly released and forced to return to Montreal, Quebec. On June 8, 1865, Carroll and a friend named O'Donnell confronted Sandford Conover in front of the William Ennis saloon. They demanded to know whether he was using the alias James Watson Wallace, the man who had spun the web of false testimony towards the Assassination of Abraham Lincoln. Carroll accepted the affidavit swearing his innocence, later explaining it in great detail to Andrew Johnson.