Catching up on recent posts, one question that did cross my mind is what would the killer have done if Yasuko’s sister and brother in-law, two more able-bodied adults, did hear the noise and responded or came over at the time of Mikio’s attack? Would he have bolted? Would he have been able to flee or would he have been trapped?
This is a very important question. I think it ties into the concerns about the noise the killer almost certainly made. How did he know he could make sounds and get away with it? / Once the sounds were made (had he counted on a silent attack), how did he know he didn't have to flee. It's paradoxical on the face of it. Either, he got incredibly lucky, which is true no matter which way you slice it. Or, he simply figured that seeing as no police had showed up after the murders, he was in the clear. Or, he simply wasn't making rational choices due to his mind-frame, his injuries / lack of blood, mental capacity / combination thereof. For him to NOT be confronted, he would require the murder of four human beings to be carried out in silence or the family next door to hear absolutely nothing.
Had he been confronted by, most likely, An Irie's husband, I think it would've been a similar struggle as seen with Mikio. The space is narrow throughout much of the house. My feeling is that he wouldn't have fled, already in so deep.
Why target Rey first when he was asleep and unaware of the killer’s presence? Shouldn’t he have quietly gone to attack one of the parents, such as Mikio who was alone in his office, first since as adults they posed the biggest threat to him? Attacking Rei is what led to Mikio becoming aware of the killer’s presence and perhaps fighting back earlier than the killer expected?
I think the answer is because the killer entered Rei's room first and, seeing him asleep, thought he would kill him first in an attempt to maintain the element of surprise. If he enters through the bathroom window, which as we saw in the reconstruction is both physically far more demanding and quite nosy (requiring a head-first drop into the room), then it makes less sense for him to cross into Rei's room and begin there. If that IS how it went down, then we wonder if Rei was his primary objective. But I can tell you that there has never been anything to substantiate that.
I agree this is most likely the perp’s first kill and perhaps they had an exaggerated perception of their own skills in defense and yielding a knife? The brutal way he attacked this family could indicate rage or perhaps a frenzy because the killer didn’t have the knowledge or skill in terms of the most vulnerable places to attack the human body to debilitate or kill a victim using the fewer strikes. Perhaps he began striking blindly as he became frustrated, overwhelmed and perhaps conflicted with guilt, shame and disgust as he took in the gruesomeness and horror of his crimes?
Yes, all very possible. I would imagine he likely underestimated how difficult it can be to strangle someone to death, even if a child. Assuming these were his first murders which, given his lack of criminal records anywhere and young age is reasonable imo, he was probably going off movies where these deaths occur in seconds. I do think you could be on to something with his bubble bursting in terms of his own self-image. Perhaps he went into that house seeing himself as a sort of ninja figure, a dealer of death. And when he realised the child struggled a lot more than expected, that to sustain pressure on the throat of someone fighting for their lives is not simple, that the situation had got away from him -- it might well have enraged him (further than I believe him to be before the murders).
I do wonder though if this perp has a history of breaking and entering or intruding into other people’s homes? Perhaps this is one of, if not the first, times the residents were present in the home or at least awake during the intrusions? I wonder if he does has a record somewhere or if there is a case in which his B&E was thwarted or he fled because he did not anticipated getting spotted or he was not prepared to fight off others?
This is also entirely possible. I can tell you that the TMPD looked at break-ins (and likely continue to do so) for any trace of him, which makes sense. My feeling is that if he did this, it's unlikely he did it in the local area or I think they would've found that connection. He has no record in Japan and, just my guess, no record in the US. Now, we don't know if he's from either nation so how long is a piece of string etc.
Maybe consuming the tea and ice cream before looking on the computer was his way to self-soothe as he came down from shock or denial or subconsciously began to confront irreversible murders and crimes he just committed?
This is perhaps crass but I went to the funeral of an ex-girlfriend's grandfather years ago. Immediately afterwards, she said she had never felt a stronger need to make love. I found that puzzling at the time but I wonder if there's a similar human instinct to live in the face of death? I myself do not enjoy shooting guns / gun culture but when a European friend came to visit me in Los Angeles, he wanted to go to the gun range. After shooting an AK-47 and feeling nervous doing so, when we walked out, we were both laughing uncontrollably. I think, again, it was an illogical bodily reaction to being close to *something* that could deal death. I'm just riffing here, of course. And it's entirely possible he was filled with fear and regret after the murders. Or satisfaction. Or giddiness. Who knows. But I wonder if, having killed them all, his body was suddenly drained (and losing blood), so he needed *something*. JMO.
I wonder if the killer was lucky or protected, perhaps by family or loved ones, who are also struggling to accept what the perp did? Perhaps they had the means and time to get him out of the country shortly afterwards and in denial never talked about it again afterwards and encouraged the perp not only to never to return back to Japan but maybe avoid discussion of his time there in general?
I would bet heavily that someone very close to him knows or at least suspects him of violent behaviour but says nothing. I too think it's a reasonable guess -- that they had the means to get him away from Tokyo shortly afterwards. I'm not saying they know he's guilty of these murders. Funnily enough, my POI lines up exactly with what you say.