Why male Madsen killed female Wall

This is an interesting news item in international press.

If you don't know about it, please google, Madsen killed Wall, okay?

From my own part, it seems to be some kind of factual gothic tale.

What I find most intriguing for a curious guy like myself, these two humans are at the height of well-being, very learned, very cultured, very healthy and active, very financially secure, in brief, very civilized and prosperous and sane.

Still, as I know about human behavior, from my reading so far, it is almost 100% Madsen killed Wall.

What do you guys here say?

And no need to bash me for being into lurid curiosity, I am human and nothing done by humans is alien to my interest, in the name of curiosity.