Tropic of Night — Michael Gruber

Jane Doe was a promising anthropologist, an expert on shamanism. Now she's nothing, a shadow: after faking her own suicide, she's living under an assumed identity in Miami with a little girl to protect. Everyone thinks she's dead. Or so she hopes.

Then the killings start, a series of ritualistic murders that terrifies all of Miami. The investigator is Jimmy Paz, a Cuban-American police detective. There are witnesses, but they can recall almost nothing of the events, as though their memories have been erased -- as if a spell has been cast on each of them. Equally bizarre is the string of clues Paz uncovers: a divination charm, exotic drugs found in the bodies of the victims, a century-old report telling of a secret place in the heart of Africa.

These clues point Paz inexorably toward the fugitive, Jane Doe, and force Jane to realize that the darkness she has fled is seeking her out, hunting her down. By the time her path intersects with Jimmy Paz's, the two will be thrust into a cataclysmic battle between good and an evil unimaginable to the Western mind.