I'm not going to comment about the killer or the victim, just the milieu.

We've always had social signaling, where people intentionally provoke or solicit attention and validation from the people around them, but the rise of social media in general, and Facebook in particular, has created a native market for attention that simply didn't exist 20 years ago. Someone looking to engage in an extreme act to garner notoriety was limited by the limits of media back then, but now they can publish in an instant, have viral reach in less than 24 hours, and become sensations, literally overnight.

We've created the perfect vehicle for people who engage in these kinds of acts - near instant celebrity. This won't be the first or the last, unfortunately.