Hi Nic!
I registered just to send this message, actually. I just wanted to thank you for all your work and am looking forward to the next podcast. I have been thinking about this case a lot these last few years, and to think that there might be some advancement to finding the murderer is great to hear.
As for your approach, I wonder if you can answer these questions:
1. The way you got the name(s) of the murderer, or his family, is that possible for the normal citizen to find out? I had contacted Japanese and American Private Investigation Agencies and I was always told that lists of American Airbase Employees are not to be found. Did it help that you already have a podcast/long history on this case?
2. Do you believe that, behind walls, the Japanese LE is actually heavily speculating that the culprit does have that US Airbase connection, they are just not saying it publicly, in order not to harm any US-Japanese relationships.
3. Your POI, do you believe he has distanced himself from this cruel act, that his mind has separated from it, as if it was a different person. If not, don't you think he might be reading this thread, listen to your podcasts etc..?
Sorry, if some of these have been asked before. If you don't have the time to answer the same questions over and over again, then please feel free to ignore. Once again, impressive work and effort, whether or not your POI is the guy, I find your effort and persistence incredible.