 But when she arrived at the Price household, she realized Price's ruse and found herself face to face with the notorious slave catcher, Philadelphian George Alberti, Jr. Black Americans like Katherine Thompson faced a precarious freedom living in the antebellum North. Despite its history of abolitionism, including passing the nation's first gradual Emancipation Act, the forces of slavery still lurked across the state of Pennsylvania, especially in the city of Philadelphia.