While the police department celebrates "solving" the case with Kristján's death, several anomalies suggest the real mastermind is still at large:
In episode 5 of The Valhalla Murders (2020), titled "In Plain Sight," the investigation reaches a critical turning point as the team identifies a primary suspect through forensic evidence, only for a social media leak to derail their progress.
: Arnar notices that one victim, Gummi, was drugged and had shallow wounds, unlike the others whose eyes were slashed.
: The "deep" truth of the series is that Pétur , the state prosecutor, was the one who raped the boys at Valhalla and murdered Tommi and Gummi. He had been paying off staff like Thor, Ómar, and Brynja to keep his secret.
: Kata and Arnar find that Steinþór has been stabbed by Kristján , a grieving father seeking revenge for his son, Tommi, who was murdered years earlier while at Valhalla.
: The team makes a breakthrough using a fingerprint lifted from a photograph of Thor and CCTV footage from a shopping mall. This leads them to Steinþór , a former boarder at the Valhalla boys' home.
: In a tense standoff, Kristján manages to disarm Kata and commits suicide using her service weapon. As a result, Kata is suspended from duty. The "Deep Paper" / Hidden Truth