The Texican(1966)

Wanted north of the border, Jess Carlin resides safely in Mexico. Then he hears his brother was killed in a gunfight with another man. Knowning his brother never carried a gun he heads north to find his brother's killer. After battling bounty hunters he arrives in Rimrock, a town controlled by Luke Starr. Starr is the man he wants but he unable to find any evidence until he is given an item found by his brother's body.