I'm confused
I'm confused about the Harper brothers. At the trial at the end of the movie we learn that Todd is accused of having murdered four people - the Harper brothers. It would seem natural to conclude that the four people he kills in the first part of the movie are, then, the Harper brothers. The sherif that catches him introduces himself to the leader of the wagon train as "Sherif Harper" and later tells the "christers" of the wagon train that Todd has killed three of his brothers. Obviously, then, Sherif Harper is one of the brothers. Timothey Carey - who is one of the men pursuing Todd - is billed as "Cole Harper" on IMDb and Allmovie. He is not credited in the movie, though, and the name Cole isn't mentioned. I assume the information is from the original short story, then.
However, if the three other deputies are his brothers, they obviously can't be chasing him because he is wanted for the murder of them! Sherif Harper later tells the obnoxious Ridge that he doesn't want to hang Todd because there's a thousand dollar reward on him. For what? Why didn't the sherif just kill Harper when he had the chance?
The most simple answer seems to be that the sherif and Cole are the only Harpers left as the movie begins and the two other men are just anonymous deputies. In that case it is rather odd that the deputies are not mentioned in the charge against Todd at the end of the movie!