Unfortunately, no, Harper because, even when they were asked on the stand, none of the family would say why.
I find it interesting that Judith said in a statement months after Jodi's murder, that she believed Ferris and Dickie "knew more than they were letting on" and that they "lied for their own selfish reasons," yet never ever, not even once, has Jodi's family called for them to be investigated further.
I also find it interesting that Dickie wasn't subjected to the same threats (if it's assumed Joseph was going to "batter" Ferris for knowing more than he was letting on and lying for his own selfish reasons).