Majo ni Kubiwa wa Tsukerarenai

When the nobility tries to monopolize magic, the crime rate surges. As a countermeasure, the Empire establishes a bureau dedicated to investigating magical crimes. Rogue, a detective, is reassigned to the sixth branch office because of his superior's-Velladonna's-scheming. There, he'll work alongside a witch who almost destroyed the Empire Because of the dangers such witches pose, they are bound with collars that restrict their power. However, Rogue's charming new partner, "the Puppeteer," has no qualms about toying with him!

(Source: Yen Press)

Note: Grand Prize winner in the 30th Dengeki Novel Awards.