The rights given to newly-freed slaves after the Civil War did not sit well with some whites in the South. Within a few years of the war, the original Ku Klux Klan arose to terrorize African-Americans and assert white power.
Washington saw a need to respond as the Klan turned violent, but it had few tools; there was no FBI then. Only the Secret Service constituted a federal police force of any kind.
Hiram C. Whitley took the helm with the aim of smashing the KKK, and his story is told in the book Freedom's Detective by Charles Lane.
The author visits with details of Whitley's life and successful campaign.