Killer? Definitely. You can't deny facts.
Murderer? Yes.
Bad person? You don't have enough information, and neither did your friend.

Acknowledging an event is completely different from understanding it. You can't deny that it happened, but you can reserve judgment on it until you do. Learning about it second-hand certainly doesn't help your understanding. It's inevitable that you'lll make some preliminary judgments on the situation, what what those judgments are need to have been derived out of some background information.

Think back to the Virgina Tech incident a few months ago. When I first heard of the news, the first thing that came to mind was not "that dude is a crazy ass psycho!" Instead, my first thoughts were "why the hell would he do such a thing?"