|Pinkerton (left) with President Lincoln|
During the Civil War, "Pinkerton had two wartime duties to perform: investigating suspicious people within the Union territory and gathering information from behind Confederate lines." This was a profitable time for the Agency, and not only in terms of cash but in experience as well.
One of the most notable cases Pinkerton investigated during this time was that of Rose Greenhow, a wealthy widow and Washington socialite who counted among her frequent guests Jefferson Davies, John C. Calhoun, and James A. Seddon, later the Secretary of War. Under the direction of Colonel Thomas Jordan (a Virginian), Rose Greenhow and her cadre of female spies sent an amazing amount of information - including blueprints of forts and military strength - via clerks, bankers, and army officers to Richmond. At one point her ring of spies had spread as far as Texas.
Finally, Pinkerton and his men observed through a window Rose Greenlaw accepting a map from an officer who then described the strength of the fortification shown on the map. Greenlaw and the officer then left the room, returning an hour later, after which the officer left. Pinkerton followed the man to the barracks where the officer, suspecting he'd been followed, alerted the provost and had Pinkerton arrested. HOwever, Pinkerton was able to get a message to the Assistant Secretary of War who, after hearing the evidence presented, summoned the suspected officer. A search of his room revealed enough evidence to convict him and have Rose Greenlaw arrested. She spent a number of months under house arrest before being transferred to the Old Capitol Prison. Eventually she was released and sent to Richmond where she was hailed as a hero and "reigned like an exiled queen."
In 1864, while trying to return to the Confederacy from Europe, the ship she was on ran aground near Wilmington, North Carolina. Although she managed to escape in a rowboat, it capsized and Rose Greenhow drowned, "weighed down by $2,000 worth of gold sewn into her underclothes."