"The initial interval between the murders was four days, and yesterday was precisely the fourth day after the last case," Minamoto Tamako said, gaining more confidence, "If the killer hasn't acted again, then Horie Kei's suspicion is considerable. As long as we continue to monitor him, new clues can be obtained."
That was her original plan, but executing it was more challenging than imagined. What was needed was not cleverness, but perseverance.
The others looked at each other and nodded in agreement with this reasoning.
They continued surveillance, rotating shifts, and two days passed quickly. Horie Kei continued working at the convenience store, heading home to watch TV after work, living a very mundane life.
During this period, the killer didn't act again, further increasing Horie Kei's suspicion.
