Without being fully aware of a family's dynamics, of which all are entirely unique, it is abstract and potentially extremely hurtful to reflect on whether or not upbringing/family relationships, etc, possibly played a part. This is an extremely small community and both families have been and continue to go through an unimaginably harrowing ordeal.
Crimes of this type often have absolutely no bearing whatsoever on the immediate or extended family and in light of the above, it would be compassionate to avoid such speculation.