Firstly, it's still an open question as to whether the Big Bang is actually the "starting point" of the universe. There are alternate theories that exist, and not any of them have yet been conclusively proven. In fact, Big Bang tends to ignore a fair bit of evidence that contradicts it.

Secondly, I object to the dissociation of logic and philosophy. Philosophy is the first field of formalized logic, as laid out by Aristotle. Just because charlatans and wannabes and apologists have made every effort to trivialize philosophical thought and necessity, doesn't mean they've actually succeeded...unless you let them.

Thirdly, there is more sound circumstantial evidence that god does not exist than there is for his/her/its existence.

Fourth, the guy goes to heaven. a) He's insane, and all insane people get a free pass according to the bible. b) Religeous determinism states that everything that happens is according to god's plan, and therefore the people he killed must have been required to die when he killed them, and by his hand. Thus, he's doing god's work.

Of course, I'm probably missing a few contradicting passages, that tends to happen in this realm.