Thanks for your question. It's nice to know that people on the other side of the world read our renshi.
I looked at the Kumu Kahua website which used to have some information about the Massie Affair. Unfortunately, that page no longer exists. But here is a link to PBS which aired a program on the Massie Affair:
Here is an article you have probably already seen:
At the bottom of the article is the email address of Professor Stannard who wrote the book, Honor Killing.
Primary sources exist in the archives here in Hawaii, but I fear the digital part of the archives do not have anything, but you might want to take a look:
The University of Hawaii has a digital library, but a cursory search did not yield anything. You might want to take a look:
Someone suggested that I read the autobiography of the governor at that time, Lawrence Judd. I haven't yet but that could prove interesting.
I know of another scholar who is writing a book on this affair. I'll send him a link to your inquiry and he may answer you.
Hope this helps.