One evening in May of 1862, Union General James Shields and other officers gathered in the parlor of a local hotel. Belle hid upstairs, listening through a knothole in the floor. She learned that Shields had been ordered east, a move that would reduce the Union Army's strength at Front Royal. That night, Belle rode through Union lines and reported the news to a Confederate Scout. She then returned to town. When the Confederates advanced on Front Royal on May 23, Belle ran to greet General Stonewall Jackson's men, braving enemy fire that put bullet holes in her skirt. She urged an officer to inform Jackson that "the Yankee force is very small. Tell him to charge right down and he will catch them all." Jackson did and that evening penned a note of gratitude to her: "I thank you, for myself and for the army, for the immense service that you have rendered your country today."
Belle was betrayed by one of the Union Soldiers who had been providing her with information. She was arrested on this day (July 29th) in the year 1862. She was inprisoned in the Old Capital Prison in Washington DC.