<quoted text>I completely understand the emotional want for non-Christian secular revenge style justice, don't get me wrong.
Wanting justice is not revenge. In a civil society there are penalties and consequences for crimes. Justice is served when the penalty for the crime is equal to the amount of damage caused when committing the crime. The price you are willing to pay for your crime should be commensurate with the atrociousness of the crime you make the choice to commit.
Not only did this woman kill the father of her three children, plus their step-mother and little step-sister, whom they loved, she forced two of her kids to draw detailed diagrams of their father's house so they could go in to murder them. Then she forced all three kids to lie to give her an alibi. What she did to her own kids was nearly as bad as what she did to the innocent little girl.
She even tried to talk the man who helped her into committing suicide and taking all the blame. He was stupid--he went on to marry her after all that. She destroyed so many lives of people she didn't actually kill outright.
Why do you think it is revenge for her to be held accountable for her actions???