Blood of the Wicked, by Leighton Gage
This is the first in the series featuring Mario Silva, Chief Inspector for Criminal Matters of the Federal Police of Brazil.  The assassination of a bishop takes Silva to the  remote town of Cascatos do Pontal.  His investigation involves him in the battle between large landowners and the farm workers seeking access to land and some measure of freedom.  A corrupt local police lieutenant and two veteran priests who side with the workers add further complications to this case.  The corruption of the local police and judiciary is stunning.  It makes our corrupt politicians look like mil-fed puppies by comparison!  Silva, his nephew Hector Costas, and his sergeant, Anselmo, fight to solve the case and bring some justice to this almost lawless backwater.  The plot is satisfying in its complexity, the characters vividly drawn.  Besides a really good story, you'll encounter the Brazil of corruption, extreme poverty and great wealth.  By the end you'll be thankful you live in the good old peaceful USA.