Boyd's espionage career began by chance. According to her highly fictionalized 1866 account, a band of Union army soldiers heard that she had Confederate flags in her room on July 4, 1861, and they came to investigate. They hung a Union flag outside her home. Then one of the men cursed at her mother, which enraged Boyd. She pulled out a pistol and shot the man, who died some hours later. A board of inquiry exonerated her of murder, but sentries were posted around the house and officers kept close track of her activities. She profited from this enforced familiarity, charming at least one of the officers whom she named in her memoir as Captain Daniel Keily, She wrote in her memoir that she was indebted to Keily "for some very remarkable effusions, some withered flowers, and a great deal of important information." She conveyed those secrets to Confederate officers via her slave Eliza Hopewell, who carried them in a hollowed-out watch case. Boyd was caught on her first attempt at spying and told that she could be sentenced to death, and she realized that she needed to find a better way to communicate.