Witches Can't Be Collared, Vol. 1 (manga)

The Las Lilte Empire, with boundless magic power at their command, has grown to great prosperity...but in the wrong hands, that power can pose a grave threat. To counteract the rampant abuse of magic, the Empire established the Magic Crimes Bureau. In the imperial capital, Elayl, hardened detective Rogue has to make a deal with the most despicable criminal of them all—because only Miseria, the witch who unleashed hell on the world, has the kind of power that can help him solve the case surrounding the Lifetaker. But when you’re dealing with convicted witches, standard investigation protocol just won’t cut it...