Correct! It was Marshal Sharp . . .
Marshal Sharp's character in the book was based on Bass Reeves.
It was no exaggeration when Jesse and Tracker eluded to the legendary bounty hunter having taken down "thousands" of fugitives.
Bass Reeves was born a slave in 1838 in Arkansas. He later escaped as an adult, and in 1875 was appointed a US Deputy Marshal - the first black marshal west of the Mississippi River. He quickly established a fearsome reputation with criminals. In the time of his career until he retired in 1907, Bass Reeves arrested over 3,000 felons! One of the arrests included his own son.
Bass Reeves was said to have a calm demeanor and to have been completely fearless in the face of danger. It is believed by many that he was the model for The Lone Ranger.
Read more about him here: