Smart Kid

[Nyarlathotep]

It's always a mistake to try to rationalize the irrational.

If I had to, however, I would imagine that this sicko had decided that the world was too painful to live in (for whatever reason, maybe they canceled his favorite TV show), so first he would "save" his family and then himself from the burden of living in it.

I don't think you are too far off the mark. Back in 1971, John List wiped out his entire family (without even having the common decency to commit suicide afterward) because he had gotten into financial trouble and wanted to start a new life. He claims that he killed his family to save them the pain and difficulty that his disapearance would bring and also because he feared that they were drifting from their church and he had to save them from going to hell. It's amazing what sick minds will do.