Dead In The Dark by Stephen Booth

Even though they work in different police organizations now, Ben Cooper and Diane Fry are both still busy with their work, murder.  Fry, who has transferred to work with a division dealing with more organized threats, is called to the murder scene of an immigrant.  He was a loner and kept to himself but she soon discovers the more common scenario for these immigrants from Eastern Europe is for them to live overcrowded in dilapidated residences, crammed in with others and paid starvation wages.  They are resented by the local inhabitants and experience prejudice wherever they turn.  This touches a chord with Diane, whose background in care left her with memories of children she lived with who faced the same unreasoning prejudice.

Ben Cooper, who is still in his small village, has been promoted to head up his team.  He now adds management worries to those of fighting crime in a remote village where he knows many of the inhabitants.  The most recent case he has brings back bad memories in the village.  A man has gone missing.  Ten years ago, the man's wife had disappeared and it was assumed by all that he had killed her.  He was charged even though no body was found but was saved at the last minute by an eyewitness account that seemed to clear him.  But memories are long and Cooper knows that his disappearance now could have its roots in those former times.

This is one of the success stories in the mystery genre.  This is the eighteenth book in the series and readers not only get satisfying puzzles but they get to see the development of the main characters over the years.  The series is called the Cooper and Fry series but, although everyone pairs the two, they themselves have a complicated relationship and don't always see themselves as a team.  Their friction makes for an interesting digression from the usual mystery series and keeps it interesting.  This book is recommended for mystery readers.