Who is Kolbein "K2" Kristiansen?

Kolbein “K2” Kristiansen is a Detective Inspector for the Oslo police in Norway. He seems to be in his late twenties or early thirties. As a young man, he is ambitious to the point that he primarily looks for the quickest and most straightforward solutions. As a result, he is often fooled, such as by the typewritten note left by Konrad. His work with Patricia proves to be beneficial, as he becomes more rational and objective in his work, ultimately coming to a number of conclusions about the case at the same time as Patricia. Unknowingly until the end of the novel, he gives Patricia a renewed lease on, and purpose in, life.