I've made a new account for this before someone "that's an interesting first post"s me.
I think the problem is with murdering someone who has harmed someone you love that it re-victimises the victim.
The victim should be in control of what happens once the truth is out and prosecution is underway. I was a victim of a peado who was a family member. We went through the courts and he was found not guilty.
I'd have needed my mum or dad locked up on top of all that drama like I needed a hole in the head. I was confused, betrayed, totally fucked up from the lack of justice. I already felt guilty for the shit my mum and dad had to deal with, I mean, my dad had already lost his whole family because they sided with the peado.
When you retaliate on behalf of a victim you lean in on the victim. You make them responsible for your anger and hurt and frustration, particularly when the victims are young. You need to support by leaning out, helping to process it.
Without knowing what I know, I'd probably want to fuck the perpetrator up big time. However having gone through it, nah, there's nothing to be gained. Try the legal route, and if that doesn't work move on, move away, get therapy and work on healing/raising awareness/campaigning for tougher sentencing. Revenge is only going to fuck your kids up more.