Yes if the Mexico passport thing on the Mcstays computer was Chase which we will never know unfortunately then he could of been planning this awhile. But looking at his criminal history it’s odd how it spans decades but he was never violent.
I know I'm late in responding here, but I wish to comment because I think we get mired down a bit in some things, wanting "all the pieces to fit". This is one of two, maybe several comments recently, about how Chase had never been violent, and so, "why now?" Well, we don't know that he'd never been violent toward people before, although he's never been arrested, apparently, for such. However, when something happens, anything, there's always a first time.
Also, we DO KNOW, that Chase has been violent and abusive to animals, and there is a strong connection (both by data and by common sense) that there is a link between animal abuse and violence against people.
All of this consideration of these things, though, really is a bit confusing to me. Yes, it's nice to know "all the details", and consider all the pieces, but as for the actual guilt/non guilt, I just don't see it being very relevant. Chase, whether previously violent or not, obviously murdered the family. I can't imagine a more obvious case. There's a pattern here, and it all leads to Chase, an obviously "not good guy", scamming Joey. Joey finds out and the family is found, murdered just afterward. Chase's gravy train had come to an end, and the bodies were found... where? Out in the desert, close to Chase's....house. Or old house. Anyway, not far from Chase's stamping grounds. Incidentally, Chase is an expert at digging holes. Also incidentally, a guy who Chase spent some time mining with vamoosed out of that desert ASAP and called the police to report him, because he gave him such a creepy, guilty vibe when he BROUGHT UP THAT ME MIGHT BE CONSIDERED A SUSPECT IN THE MCSTAY MURDERS. Alas, the tire tracks at the gravesite are consistent with, surprisingly....CM's truck. CM was the last person to see them (and he knew it!), etc., etc., etc.
CM is guilty, whether or not there is blood spatter in the home, whether or not he threw some incriminating things in a kid's backpack and threw it in the hole with the bodies, whether or not he'd ever been arrested for murder before, etc. There is no other explanation for the bashed up bodies, and the main body of evidence points to CM.
I don't mean to dismiss the discussion of all the possibilities about backpacks, and previous violence, I just hope the jury doesn't get caught up in them. There are many, many possibilities regarding many of the details that we'll never know, this being life and life is messy and all.