Youngjae sat at his desk, analyzing the crime lab’s report. His office was cramped but tidy. A pile of papers was on the right side of the table, while some thick books were to the left. He removed his reading glasses and rested his back on the backrest of his swivel chair.

The victims of the serial murderer had the same extensive injuries; multiple stab wounds caused by knives and scissors, crush injuries to both hands, fractured legs, wounds caused by dart arrows, and scalding on their feet. Their ankles had deep scars, marks from chains. He hung them up and down.

“What kind of animal would do this?” he...