Dogheaded Death

First-century Alexandria is the backdrop for this spirited but often implausible historical murder mystery, the first in a projected series featuring the sleuthing centurion Gaius Hesperian. A palace guard of Nero's who has a detective's intuition, Hesperian is called in to investigate the slaying of Odysseus Memnon, a grain merchant and shipping magnate. Memnon himself had suspected that one of his relatives would attempt to kill him after he announced his intention to give every last drachma to the ``obscure Jewish heresy called Christianity.'' Hesperian is an unusual investigator for his day, solving crimes through questioning, not torture. Through adroit interrogation of the family, the slaves of Memnon's estate and local merchants, he uncovers not only the killer but an illicit affair and a murder motive much more complex than greed. Along the way Nelson ( TimeQuest ) pastes curious period details onto his already impressionistic setting. (Dec.)