Death Walks in Laredo(1967)

Whitaker Selby, Lester Kato, and Etienne Devereaux, three eccentric gunmen, discover they are brothers. Their father left them all a mine located in Laredo, Texas. But they discover that Julius Caesar Fuller, the town's greedy landowner (who fancies himself Caesar) has taken control of their mine. They band together to fight Caesar and his black clad gunmen to repossess their mine and avenge their father.