1) The snowman
"In Oslo, after the first snow of the season has fallen, a woman disappears, and a sinister snowman is left in her wake. As irascible detective Harry Hole realizes that this is only one of multiple disappearances, he begins to think a serial killer may be at work--and may be drawing in Hole personally and intentionally"--
Detective Harry Hole volume 9
Determined to prove the innocence of a young man he helped raise, disgraced former cop Harry Hole embarks on an increasingly dangerous investigation linked to Oslo's most virulent street drug.
3) The leopard
After two young women are found dead, both drowned in their own blood, Inspector Harry Hole is compelled to return to Norway to see his dying father and to investigate the brutal crime, which may be the work of a serial killer.