Mary Belt's will stipulated that Laurena be sent to live with a sibling of Rachel Pratt's while Sophia and Alethia were to stay at the Chelsea Plantation.

This is further supported by the fact that Joseph Doughtery, who purchased Alethia from Rachel Pratt, served as President Jefferson's footman.

After 1836, Alethia began purchasing the freedom of her neighbors, including Charlotte Davis, John Butler, and Lotty Riggs and her four children.

During the Snow Riot of 1835, Cook temporarily fled the city when a white mob attacked and burned down the one-room schoolhouse.

Alethia was a businesswoman, owned real estate, and supported and sponsored educational and religious institutions for the free Black community in Washington, D.C. She was a Methodist church member partly because she was drawn to their position on slavery.

Alethia's safety was jeopardized by the Snow Riot in August 1835, which started as a labor strike but extended into attacks on free Black people.