That's the only thing that comes to mind reading the transcripts and looking at his "artwork" (which he knows was being copied, since so many say "COPY THIS").
On a more gruesome note, in the transcripts Malvo says the Home Depot shooting was from 132 yards, and he was positioned across the street at the Wilston School. That was pretty obvious from the start.
These documents don't show that Malvo's "insane," they show he's a thoroughly twisted and evil psychopath who should be eradicated from the planet post haste.