From everything I’ve seen here, it’s clear to me that law enforcement has suspicions regarding the family. That of course does not mean that they are correct, but it’s obvious that is an angle they are actively exploring.
I remember during the Gannon Stauch case, law enforcement also discussed there being a “parallel investigation,” one that was traveling down two roads, foul play and that of a lost child.
Of course in that one, they were positive that the former occurred, but didn’t want to tip their hand.
Every case is different, and every law enforcement agency is different. That being said, I’d be very surprised if this did not involve foul play.
There are a lot of red flags here.