I have altered my own theory about the ultimate fate of the McStay family (see previous posts here for backstory).
A few troubling facts make me now believe that Summer McStay (or Lisa Aranda or take your pick of one of her many aliases) probably had her husband Joseph killed and went into Mexico with a man with whom she was romantically involved.
I admit this is largely intuition, but I base this also on a constellation of troubling facts.
1. At first, I was unsure which adult was searching the internet for passport requirements for entry/exit from Mexico. I now believe this was Summer because a story in one of the L.A. papers also revealed that Summer was taking a course to learn Spanish in the months before the family's disappearance..
2. Joseph's brother when asked by Nancy Grace whether he thought Summer could bring harm to her husband did NOT categorically deny this possibility. His answer was something like "I hope not." This sort of doubt implies to me he knows more about tensions or troubles in the relationship, pre-disappearance.
3. Many sources seem to believe it is definitely Summer and the children in the videotape of four people walking into Mexico by night (and the timing--one hour after the car was left nearby!) but many (including Joseph's own mother) do not believe the man who is holding the hand of the other child (Chubba) is really Joseph McStay. As his mother pointed out, his voluminous hair would have shown up on silhouette--even if tucked in, the bulk of the head would appear differently than it does. And I just put a lot of stock in the mother's belief. That she would recognize her son.
4. People have reported that Summer McStay was involved in illegal real estate dealings. I can't verify this but this information has appeared on more than one reputable site.
I just now intuitively believe that Summer McStay engineered the disappearance, and if there was another man in her life I don't think that bodes well. I mean in regard to the chances that Joseph Mcstay is alive.
To presume an abduction of Summer and the children by a stranger when there is so much indication of planning for this escape into Mexico seems implausible.
Was the purchase of toys found in the abandoned vehicle a ruse to distract the children from the disturbing turn of events...possibly a stay in a motel with their mother and a strange man....and the absence of their father?
And I used to wonder at the several days that elapsed before the "family" crossed over into Mexico.
But if you have to get rid of a body, that takes time and preparations.