Death of the Mantis by Michael Stanley

From Library Journal: "When his childhood friend Khumanego, a member of the nomadic first peoples of Botswana, begs for his help, Detective David "Kubu" Bengu responds eagerly. A local park ranger has been killed in the Kalahari, and three nomads are being held for the murder. Kubu convinces the local authorities to free the trio, but he wonders what he's missing when a second murder-this one involving a Namibian PI-is discovered in the same region. As the secret lives of the victims are revealed, the variety of possible motives expands at a dizzying pace. Impossible to put down, this immensely readable third entry from the duo of Michael Sears and Stanley Trollip delivers the goods. Kubu's painstaking detecting skills make him a sort of Hercule Poirot of the desert. Grimmer than Alexander McCall Smith's Precious Ramotswe mysteries but not oppressively violent, this series can be recommended to a wide gamut of readers."