Rennie Airth's River of Darkness is a police procedural set in rural England shortly after W.W. I. John Madden, a Scotland Yard detective has been sent to a town in Surrey where a brutal murder of an entire family looks to be a robbery gone wrong. Madden immediately suspects something as the wounds on the bodies display a striking resemblance to bayonet wounds and ones skillfully inflicted at that, indicating military experience.
Madden has his own torments -- it's interesting that classic, early detective novels had detectives with bizarre habits; modern detectives all suffer some rather melodramatic angst -- as his wife and daughter died in the great influenze epidemic and he suffers from psychological and physical wounds suffered in the war. In that respect, Madden echoes Charles Todd's Scottish detective , who also faces his own demons from the war.
Airth introduces several interesting characters including the insecure constable Billy Styles and Madden's new love interest, Dr. Helen Blackwood. The killer's mind is revealed in contracting vignettes. His response to his war experiences differs sharply, Airth's point being that survival takes many forms.
River of Darkness will grab your attention and hold it. Apparently, it's the first in a projected trilogy. The second volume, The Blood-dimmed Tide, is due to be released soon.