River of darkness

the long version

Upon its original publication, River of Darkness awed readers who look for intelligent, well-plotted psychological mysteries. This "fine, frightening piece of work" (Kirkus Reviews) introduces inspector John Madden who, in the years following World War I, is sent to a small village to investigate a particularly gruesome attack. The local police dismiss the slaughter as a botched robbery, but Madden detects the signs of a madman at work. With the help of Dr. Helen Blackwell, who introduces him to the latest developments in criminal psychology, Madden sets out to identify and capture the killer, even as the murderer sets his sights on his next innocent victims.