Devil all the Time - Donald Ray Pollock

In Knockemstiff, Ohio, war veteran Willard can't save his beautiful wife, Charlotte, from a slow death by cancer no matter how much sacrificial blood he pours on his 'prayer log'. Carl and Sandy Henderson, a husband-and-wife team of serial killers, trawl America's highways searching for suitable models to photograph and exterminate. Preacher Roy and his crippled virtuoso-guitar-playing sidekick are running from the law.