Here is an excerpt of the civil war and what the slaves have done as far as counter intelligence was concerened and how they managed to make it possible.
You will follow the link after reading and you will see more.
The Civil War: Black American Contributions to Union Intelligence
P. K. Rose
P. K. Rose is in the Directorate of Operations.
"Black Dispatches" was a common term used among Union military men for intelligence on Confederate forces provided by Negroes. This source of information represented the single most prolific and productive category of intelligence obtained and acted on by Union forces throughout the Civil War. In 1862, Frederick Douglass wrote:
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