Set in 1999, Edgar finalist Stanley’s excellent eighth mystery featuring Botswana’s Det. Sgt. David Bengu, the author’s second prequel (after 2020’s Facets of Death), finds Bengu, affectionately known as Kubu (or hippo, for his girth), still learning the skills to become an astute and observant homicide investigator. When excavations get underway for a water project, a Bushman’s skeleton is unearthed, and Kubu, who’s complained that his daily work is dull, is sent by his boss to see what the pathologist, Ian MacGregor, concludes about the cause of death. MacGregor’s job is made near impossible by the age of the remains, which he dates to more than 10 years earlier. Foul play seems even more probable when MacGregor finds eight more Bushman skeletons of similar age. The prospect of a massacre cover-up raises the stakes. Meanwhile, some present-day murders give Kubu plenty to occupy him. Stanley (the pen name of Michael Sears and Stanley Trollip) gets everything­­—the dialogue, the terrain descriptions, the plot beats—right. More prequels fleshing out this complex and endearing protagonist would be welcome. (Self-published)