This makes it sound more like it's a fishing expedition for evidence to use in other investigations, or to find evidence for a more severe punishment, both of which one can morally agree or disagree with, but is it how justice should work? I honestly don't know, but I think probably not.
It's a detestable crime, which is exactly why we must not allow the law to be bent out of shape because of that, as the results will be used in other cases where our moral compass maybe wouldn't sway our judgement as much.
The only justice we can enact, flawed at rational reasoning as we are, is a dispassionate justice. One where we as much as possible defer to the few rational facilities we have. Weak, but nonetheless, logical and rational thinking, is what we must base our arguments upon, as we are so easily swayed by our instinct to protect our children at any cost, often with little regard to what consequence it might have in a distant future.