A Conspiracy Of Faith by Jossi Adler Olsen

Things are much the same in Department Q in the Copenhagen Police Department.  Detective Carl Morck is still the grumpy policeman shuffled off to the basement and given cold cases to solve; cases no one expects he can make progress on.  His assistants are the same ragtag bunch of misfits.  Hafez Assad, hired as a janitor and an immigrant whose papers wouldn't stand much scrutiny, is overqualified for his job and sees connections no one else does.  Rose, a policewoman so hard to get along with that she has been given to Carl, does what she does, mostly nothing with occasional flashes of brilliance.

The latest case couldn't be much colder.  Department Q is given a message.  Apparently it was found in a bottle.  The bottle drifted to Scotland, where someone found it and put it on a shelf.  Years later, the message was taken out and it was determined to be a plea for help from someone who claimed to have been kidnapped.  This message, at least a decade old, is now Carl's job to decipher and decide if a crime has been committed.

Thus opens one of the most challenging cases the department has ever seen.  As they work on the case, they determine that indeed a kidnapping had taken place.  Two children, one a brilliant young man, had been kidnapped.  The gifted man had written the note.  Only one returned home.  The crime was never reported.  Even worse, as the case is unraveled, it soon becomes apparent that this was not a solo crime.

There is a serial killer working in the murky underground.  He targets fundamentalist religious families, who typically have large families.  His plan of attack is to kidnap two of the children then demand a ransom.  Once the ransom is paid, he kills one child and returns the other, saying that he will know if the crime is reported and will return to kill more of the children.  The terrified families tell their friends that the missing child has broken religious laws and has been excommunicated and sent away.  The killer has struck over and over through the years and it is up to Carl, Assad and Rose to stop him.

Jossi Adler Olsen exploded on the crime scene several years ago with this series.  Readers are quickly entranced with the characters and the mysteries that twist and turn, but eventually are solved by Department Q's unconventional methods.  This third mystery is another stellar contribution to the rapidly expanding field of Nordic noir.  A Conspiracy Of Faith is recommended for mystery readers.