"Although the furniture colors and details here differ somewhat from Room 501 downstairs, when we arrived at the apartment entrance just now, I remembered that the lights in Room 601 were off," Jiang Xia said. "The victim was in darkness and somewhat dazed, so it would have been difficult for him to distinguish subtle differences like colors. He would have thought he was lying in his own home."
"With this layout in place, all you had to do was take advantage of the victim's escape habits—the manager said that the victim had a habit of jumping from his own balcony to the rooftop of the building opposite. If the manager could notice that, then Mr. Kanda, his upstairs neighbor and 'friend,' would have had no trouble noticing it either."
Jiang Xia looked at Doctor Kanda. "The sequence was probably like this: before we met at the café, you went to the victim's home first and knocked him unconscious somehow. Then you opened the French window leading to his balcony, creating the illusion for the next person to enter that the victim had left through there.
"Then you secretly moved him upstairs to your own Room 601, turned up the volume on his phone, and came downstairs to meet me.
"After we arrived at the café across the street, which we had arranged to meet at beforehand, and agreed to come to the apartment with you, you called the victim. On the surface, that call was to tell him we were coming and have him prepare in advance. But in reality, while the victim was being awakened by the ring tone and was still groggy, you frightened him with something like, 'The people threatening you are already at your door.' And then..."
At that point, Jiang Xia seemed to remember something.