Service of all the Dead / Colin Dexter

From amazon.com review:

In the Service for All Dead Morse walks the dark pathways of the mind. He almost backs into the lives of seven people entwined with St. Frideswide's parish in Oxford. With a keen understanding of human nature, much akin to that of Reinhold Niebuhr, he begins to untangle a series of crimes that began two years before. With a chain of deductions and intuition Morse takes you to a breathless and satisfying conclusion to five and perhaps six murders.