The Shrunken Head — Robert L. Fish

Captain José Da Silva has the daunting task of finding a murderer. Hired by the Brazilian Foreign Office, Da Silva sets out to end these jungle killings, but doesn't quite have all the facts. When Agent Wilson shows him one of the victims -- not all of him, just his shrunken head -- Da Silva realizes that this murder case isn't as open-and-shut as it seems. Now he must investigate, evading the powerful magic and numerous mysteries of the Amazon jungle.