So far, it doesn't sound like terrorism to me.
Sounds like a guy whose life was coming apart at the seams (taxes and/or pending divorce, etc.), and he decided to go out with a bang.
I could be wrong, but that's what it smells like at this point. Details will tell the story in time.
While it probably isn’t organized terrorism, it is a terrorist act. It was designed to hit a visible, relevant target — that’s terrorism in my book.