Jiang Xia looked over Officer Sato's notebook. "After killing Mr. Daimon, the murderer used some method to lock the door from the outside, creating a second locked room. The purpose of these two locked rooms was to make people think everything was the work of a vengeful spirit, leading the police to believe that the real culprit was the eldest son, who 'killed his father, returned to the Audio-Visual Room, and committed suicide out of guilt.'
"To reinforce that impression, the murderer also took advantage of the old lady's deep belief in ghosts and spirits, deliberately letting her see an armored samurai walking through the courtyard.
"The old lady's routine is very fixed. Every year on General Shuyū's death anniversary, she prays in the Buddhist Shrine. So the murderer deliberately passed through an angle where she could be seen, hoping to obtain the corresponding testimony afterward.
"But in fact, while the old lady's testimony guided everyone toward that legend, it also exposed certain characteristics of the murderer.
"There was no long sword on the armored samurai's left side. In other words, the sword was being held in the right hand at the time—the murderer was left-handed."
The old lady: "?!"
The eldest daughter-in-law: "!!"
Suzuki Sonoko suddenly remembered something as well, and turned with them to look at the youngest son. "I remember you're left-handed! When you helped the maid sign her name, you used your left hand!"
Daimon Yoshirō looked panicked. "I am left-handed, but I didn't kill anyone! Besides, if the armor held the sword in its right hand, then that means he should be right-handed, doesn't it?!"
Officer Shiratori sized up the wealthy second generation his own age. "The murder weapon that appeared in the Audio-Visual Room was a sword with its sheath. When holding a sheathed