When she returned to Richmond, Mary was arrested and imprisoned for nine days for claiming to be a free person of color without having her free papers. During her confinement, she was constantly questioned and interrogated. Mary knew how to protect herself: she gave false names to her jailers and lied about her identity. After her release from jail, the chances were that she would be sold into slavery again. To save Mary from this fate, Elizabeth’s mother paid a fine and secured Mary’s release.
By September 1861, Elizabeth Van Lew became involved in pro-Union activities in Richmond. She began developing the contacts for what would be known as the Richmond Underground, the spy ring she would organize until the end of the war. Its members collected intelligence from both Union and Confederate troops, smuggled the information to Union leaders outside the city, and helped Union soldiers escape from behind enemy lines. Elizabeth recommended Mary for a job as a servant for the Davis family in the Confederate White House, giving the Richmond Underground the upper hand in having a source so close to the leader of the Confederacy.
Mary’s education and excellent memory would serve her well. She knew what to look for, and she could keep an eye out for certain information on troop movements while she was cleaning the President’s office. Blending in easily, she kept her ear to the door and eavesdropped on conversations. At the end of the day, she would write down all of the information she had gathered that day and smuggle it out to Elizabeth. Elizabeth would then code the information and send it to General Grant, significantly improving the Union advantage.
After the war was over, Mary earned her freedom, but she stayed in Richmond. Her education and teaching experience in Liberia was highly valuable: she began working with the Freedmen’s Bureau, teaching former slaves. Within a few months, Mary traveled to New York, giving two speaking engagements about her experiences during the Civil War. For each of these engagements, she gave two separate aliases and shared different information about herself, much like she had when she first came back to Richmond from Liberia. One can only assume Mary felt safer this way, with fake names and identities to hide behind, especially as a black woman who plotted against the Confederacy. In these speeches, she not only described her spy activities, but she also used them as a platform to support voting rights and equal rights for African-Americans.