I've seen "Las Poquianchis" in Spanish without subtitles. I speak Portuguese so I can only understand Spanish when it's spoken slowly, so I couldn't follow everything that happens in the film. Anyway I've understood the story in its basic lines.
"Las Poquianchis" tells the story of the girls who were taken from their families under false promises and sent to the Poquianchis brothel. On arriving there, the girls were virtually kept as prisoners and forced to work as prostitutes - they were mistreated and sometimes even killed. Government officials took part in this scheme and took their share of the profits. A government investigation discloses the activities of the Poquianchis brothel and terrible crimes are discovered - the corpse of a girl killed is unburied and many other revelations will follow. A web of horror is uncovered to the public and it's revealed that the pillars of society (government officials and the local respectable citizens) took part in it. The girls themselves accepted after a while their "fate" and some of them after reaching a higher position didn't hesitate in using their power to crush the other ones - the Poquianchis brothel was directed by women who once had also been kidnapped, forced to work as prostitutes and mistreated. These ones and all the others who helped them in some way are to be be tried by the tribunal. What may be disquieting for some of you is that the film doesn't show us who are the bad people. "Bad" is not located in a definite place and neither can be traced to someone or some organization. Who bears the guilt of everything? The managers of the Poquianchis brothel? The government? No, not so easy! Even the media that uncovers the case does it not for idealism - they see in the Poquianchis the golden chance to sell more newspapers etc..
Alongside the Poquianchis story, the film tells us a parallel story filmed in black & white that follows the father whose two girls were taken to the Poquianchis brothel. He and other small farmers are fighting legally for their own land, but they are fighting against a bigger enemy. Their fight is hopeless - corruption will stall them and deaths will ensue. As for the government officials, they are just cogs of a great wheel but who really runs the machine? The government or human greed? It's not easy to answer this question, because government is an abstract word. There are hundreds of thousands of people, or more, contained by this word government but be it the government officials, be it the others all or them are fighting for their own interests ("legitimate" or not). Some fight for bare survival, for their land, some for more money, for their position. The girls who provoked the wrath of the Poquianchis managers suffered a beating (so severe that it sometimes led to death), administered by their own companions in suffering, acting under the orders of their superiors (who had once been themselves victims of the same system). A vicious circle. That's the way society works.
"Las Poquianchis" is a political film, but a political film in the greater sense of the word, that is, a political film bearing a capital P. It is not like those films made by Costa-Gavras that offer us an "objective" cold analysis of some socio-political subject. "Las Poquianchis" is like a punch in the gut the film is not cold, but, on the other hand, it is neither sentimental nor a tear-jerker. It is raw and emotional (but not in the usual way). This is not your typical Mexican melodrama (even if I like some of them). It's a powerful film. I will try to see some other Cazals's films. Maybe "Canoa".