The Snowman by Jo Nesbø (Harry Hole #7)

SOON THE FIRST SNOW WILL COME.
A young boy wakes to find his mother missing. Their house is empty but outside in the garden he sees his mother's favourite scarf - wrapped around the neck of a snowman.
AND THEN HE WILL APPEAR AGAIN.
As Harry Hole and his team begin their investigation they discover that an alarming number of wives and mothers have gone missing over the years.
AND WHEN THE SNOW IS GONE...
When a second woman disappears it seems that Harry's worst suspicions are confirmed: for the first time in his career Harry finds himself confronted with a serial killer operating on his home turf.
...HE WILL HAVE TAKEN SOMEONE ELSE.