I don't pretend to understand the mindset of a suicide-murderer, but I'll make a guess. Perhaps they are in pain due to mental illness and want to end their li

I don't pretend to understand the mindset of a suicide-murderer, but I'll make a guess. Perhaps they are in pain due to mental illness and want to end their life. The guilt of their children living without them is preventing them from moving ahead with their plan. By ending their children's life, it allows them to be free of that guilt and commits them to a course of action where they will end their own life.