Herod's Law (1999)

After the corrupt former Mayor is killed by the peasants, poor janitor Juan Vargas is appointed new Mayor of a desert town in central Mexico. Although he tries to bring the motto of the ruling party to town (modernity, peace and progress) he realizes soon that there's nothing to do against corruption... except to become corrupt. Step by step, helped by his pistol, Juan Vargas becomes the law and the worst Major in the town's history.