I still think -- that in the end -- no laws are going to protect anyone nor prevent anyone from murdering another human. How many they murder depends on how well they plan it. But no "law" is going to prevent them.
I don't think a normal mind can possibly comprehend the criminally insane mind. WE just don't think that way.
We can't explain it -- I don't think we can stop it -- and, while we don't want to -- I think we just have to accept that from time to time bad stuff happens.
Perhaps I've said the Serenity Prayer too often... it's that last line of the first verse....
God grant me the serenity
to accept the things I cannot change;
courage to change the things I can;
and wisdom to know the difference.