From the National Archives:
As head of a a very successful spy ring in Richmond, Virginia, Elizabeth Van Lew provided regular and timely information to Generals Benjamin Butler and Ulysses Grant, assisted escaped prisoners, and even placed a spy [Mary Elizabeth Bowser] in Confederate President Jefferson Davis‘ home. After the war, her trusted lieutenant, William S. Rowley, sent this letter to Secretary of War Edwin M. Stanton claiming the government owed him money for his work as an agent.
Few official records of Van Lew’s accomplishments exist. In December 1866, she asked the War Department for all records of her espionage activities. The records were never returned to the War Department. Van Lew probably destroyed them.