I think somebody came across either soft ground or a smell or something like that on the property and they called it in. I don’t think MB cracked and just told the truth. I think she’d have kept lying for the rest of her life. AB and WM aren’t likely to be the source of information IMO because if they had it, they’d have given it up when they were arrested. They were out of jail, away from LE pressure when EB was found. I could be wrong, but I don’t think either of them knew or helped cover it up.