A novel by a Norwegian writer called Jo Nesbo (with the slashed through "o" letter I don't know how to type) named Snowman. It's really good.
I have read one novel by Jo Nesbo called "Nemesis". It was quite good but I didn't enjoy it as much as novels I have read by Karin Fossum, Arnaldur Indridason and Johan Theorin so I have placed Nesbo behind them in the list of books I must read. I do like the character of Harry Hole.