I'm at a loss

A Columbus, Ohio teen is facing forty years in prison for live streaming her seventeen-year-old friend's rape on Periscope.

Let me repeat that:  A Columbus, Ohio teen is facing forty years in prison for live streaming her seventeen-year-old friend's rape on Periscope.

Leaving aside the fact that the above statement may use the word "friend" in the most convoluted way in the history of writing, can somebody please explain this to me?  What would possess any person to film a friend's rape?  Is it abject stupidity?  Is it an utter lack of empathy a la a psychopath?  Has social media changed the world as I knew it so much that I just don't recognize it anymore?

I've literally been trying to wrap my head around this young woman's actions for two days and I cannot.  It is completely beyond me.

Peace,
emaycee