As a Detective, It's Reasonable for Me to Have a Police Girlfriend.

Summary

Hei Mu Zi and Qin Shi Yu analyzed library surveillance footage, revealing a woman who frequently lingered near a specific bookshelf. Yan Zheng speculated this was where messages were exchanged, prompting a search for suspicious individuals. They identified a man linked to the woman's activities on the day before a murder. Yan Zheng noted the cleaner's role and decided to examine nighttime footage, suspecting someone could sneak in unnoticed. Upon reviewing the footage, they spotted a shadow indicating a potential break-in. Disguised as a student, Yan Zheng inspected the library, discovering clues that confirmed the use of a hidden message system. His investigation led him to a restroom, where he utilized a UV light to reveal coded messages, suggesting a sophisticated criminal operation.

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