兄妹 少女探偵と幽霊警官の怪奇事件簿 (Series) favorite_border

[DeepL Translation - needs review] Volume 1 Introduction: Two years have passed since her brother Keiichi, a police officer, disappeared. Hotaru Akagi, now in her first year of high school, is confronted by the ghost of a maniac dressed as a policeman...? The brother and sister team up to tackle mysterious cases and events!　A mysterious mystery drama!

(Translator: DeepL)