Follow on to my previous comment: They were going to the in-laws to pick up the kids. Visitation during a custody battle resulting in death. This is not the first or last grandmother who killed her daughter-in-law during a visitation exchange.
I showed my daughter w/2 kids and an ex that routinely exchange the kids.
Cold blooded murder 2X. Oakie panhandle is a very lonely place. How would you figure that you would every get away with double murder without the shoveling part and the shut up part.