Into Thin Air by Ørjan N. Karlsson

When nineteen-year-old Iselin Hanssen disappears during a run in a popular hiking area in Bodø, Northern Norway, suspicion quickly falls on her boyfriend. For investigator Jakob Weber, the case seems clear-cut, almost unexceptional, even though there is some suggestion that Iselin lived parts of her life beneath the radar of both family and friends.

But events take a dramatic turn when another woman disappears in similar circumstances – this time on the island of Røst, hundreds of miles off the coast, in the wild ocean.

Rumours that a killer is on the loose begin to spread, terrifying the local population and leading to wild conspiracies. But then Jakob discovers that this isn’t the first time that young women have vanished without a trace in the region, and it becomes clear that someone is hiding something … and another murderous spree may have just begun…