The Purity Of Vengeance by Jussi Adler-Olsen

When a cache of unsolved missing-person files is handed to Copenhagen’s cold-case unit Department Q, detectives Carl Mørck and Assad reopen a decades-old trail that leads from the city’s underbelly into the heart of respectable society. What begins as a search for vanished women becomes an investigation into institutional cruelty, long-buried secrets and a calculated campaign of violence and cover-up, forcing the team to confront powerful enemies and the moral costs of uncovering the past.

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