Obsidian and Blood by Aliette de Bodard

Let me tell you this: if you ever sat down to yourself and said "You know what the world really needs? An Aztec noir murder mystery with strong fantasy overtones," then you can rejoice, because Aliette de Bodard's Obsidian and Blood trilogy (Servant of the Underworld, Harbinger of the Storm and Master of the House of Darts) delivers exactly that, and quite a lot more. Granted, most of that "more" it delivers is blood, but this is an Aztec series, and the main character Acatl is the High Priest of the Dead, who relies on sacrificing animals in order to commune with the gods.
Each of the three novels in the series tells a standalone story; taken together, the trilogy deals much more broadly with political machinations in both the human and the divine worlds. Each of the murders Acatl is called to investigate takes place at a particularly turbulent time in Aztec mythology—times that could result in the rending of the earth and the end of the Fifth World, leading a new and much more malevolent god to ascend in the Sixth World. It's not enough that Acatl has to deal with human conspirators, either, as he must use his powers as a priest to intervene in the individual machinations of the Aztec gods.

The mystery portion of the novels aren't much, really—you've got your locked-room murder, your covert assassination, and your mysterious magical illness, and Acatl spends most of each book investigating the individual pieces of each puzzle. But I've never been much of a mystery novel reader, so I can't say for certain how well these tropes are handled; what I can say is that it's clear that de Bodard has done extensive research into the Aztec culture and stays as accurate as possible in these novels. It's fantasy, but only in the sense that Aztec mythology is presented as though it were reality; something quite different in a genre largely defined by its reliance on Totally Not Medieval Europe settings.

Whether you take it as historical noir or as a highly accurate fantasy, it's hard not to enjoy the Obsidian and Blood books—it's a perfect fit for those looking for something different from their usual fare, but still exciting in ways they're used to. And even though it's the wrong culture, it's still a fitting read in this apocalypse-minded 2012—and likely a great deal more accurate than the bumper crop of Mayan apocalypse fiction.