The Last Sun — Michael Jan Friedman

It's 2012. Maxtla Colhua is an Investigator for the Empire--an Aztec Empire that, having successfully repelled Hernan Cortes in 1603, stretches from one end of what we know as the Americas to the other. Now the Last Sun is upon Maxtla's people, and someone has decided to punctuate it with a series of grisly murders reminiscent of the Aztecs' pagan sacrifices in ancient times. Can Maxtla find the killer before his city is ripped apart and the Last Sun becomes the death knell for the Empire?
Aztan: The Last Sun is the first in a series of brand-new murder mysteries set in an exciting world that never was but could have been!