The Blood Oath

First, the setting of the story:
Fleetwood is a small town circa 1911, located in the swamps in Southern Mississippi between the fictitious cities of Shoenburg and Meridean (note: the location is generic. Could be in the Everglades of Florida)
The town is divided into two factions: the town dwellers who are mainly employees of a fictitious company who capture snakes and alligators and turn their hydes into boots, clothing, etc. The second faction consists of the farmers and their families, who live at surrounding farms. These people are the older families who received their land when the owner of a prior cattle empire sold out his business and gave the land to the drovers, who became settlers.
The two factions do not associate much. Especially the farmers, who discourage associating with the others.
At the time of this story, the town is living in an unknown fear due to the fact that over the past nine months, four boys between the ages of 11 and 15 have been murdered and left in alligator pits. Nobody knows why.
At a Shoenburg college reunion, the town doctor, who has lost a son due to a previous typhoid epidemic, meets and adopts a ten year old orphan boy who is a mute due to a previous physchogically damaging incident that left him an orphan. The town doctor takes him back to Fleetwood to live.
As he adjusts to living in his new environment, which includes dealing with bullies, and becoming close friends with an outcast young teen, he encounters and witnesses events that relate to the murders of the boys and why they are happening.
Eventually, he and his friend encounter the killer and are nearly murdered by him, but escape. From this point, he becomes a target of the killer although he had nothing to do with the events that are causing the murders.
The doctor, at this point, dedicates himself to solving the murders before the killer can get to the boy.
The reasons for the killings go back to a horrifying incident that happened in the town 30 years ago, i