On April 12, 1865, just days after the last major battle of the Civil War, a Confederate double agent named Godfrey Joseph Hyams approached the U.S. consul in Toronto claiming to have information about a plot by Blackburn to infect Northern cities with yellow fever. Hyams said he and Blackburn had been introduced by Confederate agent Stuart Robinson at the Queen's Hotel in Toronto in December 1863. According to Hyams, he had agreed to help Blackburn smuggle trunks of clothes used by patients infected with yellow fever into Boston, Massachusetts; Philadelphia, Pennsylvania; Washington D.C.; New Bern, North Carolina; and Norfolk, Virginia (the latter two cities being occupied by Union troops). Hyams said he was instructed to sell the trunks' contents to used clothing merchants, and that Blackburn, subscribing to the common nineteenth century belief that yellow fever could be spread by contact, hoped that by dispersing the "contaminated" articles throughout these major cities he could trigger an epidemic that would cripple the Northern war effort. Hyams further alleged that Blackburn had filled a valise with fine shirts and instructed him to deliver it to President Abraham Lincoln at the White House, saying they were from an anonymous admirer. Upon completion of these tasks, Hyams said, Blackburn had promised to pay him $60,000. Hyams claimed he delivered the trunks as agreed, but did not attempt to deliver the valise to President Lincoln. According to his testimony, he never received more than nominal compensation for his efforts, partially prompting his decision to reveal the plot to the authorities.