In the Dark: A Novel (A DI Adam Fawley Novel, Book 2)

In the Dark: A Novel (A DI Adam Fawley Novel, Book 2) by Cara Hunter

A woman and child are found in a senile professor's basement. A dead person is also found. DNA evidence shows the boy is the child of the man. The girl says they were slaves stuck down there. However, after detective work, it turns out that the man was the victim instead. This is a fairly gruesome mystery with many twists and turns.