I don't think I've heard of, or read about James Armistead, Maestro. However I'm aware that some Black slaves at the time(Men and Women) were very good at "spying" for Whites who did not want to set them free yet.

Below I would like to introduce you to Joseph Carter, the slave who hung his overseer from the Oak tree. On America's Independence Day, Joseph Carter turned celebration into judgment. Under the oak tree, he became the executioner in rags, hanging his overseer and defying a world built on chains. This is the forgotten story of vengeance, silence, and justice that "hung higher than kings".

Joseph just had no freedom to celebrate, in the silence of midnight he turned the nation's proudest holiday into a trial of blood.