Apparently not. See post 73.
Planning is inconsistent with "snapping". And it looks like he did a lot of planning (brought guns, brought car full of gas, Email messages, etc.) and has done this before. Had he really gone berserk, he might have shot one person but not two - he would have shot one and fled alone. The eyewitnesses are probably going to testify that he hunted the parents down - since the other kid managed to hide in a bathroom. He had a plan, and he coolly and methodically executed it.
I stand by my prediction. When the facts come out, you're going to see a lot of previous problems that were ignored or minimized. The penalty phase particularly is going to be horrendous.
Reportedly, Ludwig shot the father in the back of the head as was being escorted from the house. The mother's body was found sitting with a blanket over her legs, so it doesn't sound like he "hunted the parents down," either.
As far as what some kid posts on a website, I place no real credibility in it.
About those "warning signals" that a kid is going to go astray, what about Kara? She was a rebellious 14 year old, who grew up way too fast. Sending nude pics of herself to the boyfriend, having sex with him, disobeying her parents by staying out ALL night..my god..her poor parents had their hands full. She was out of control. No telling WHAT she and David were cooking up.