Rape: Why is it so hard to combat?

The horrific gang rape of a 16-year-old girl in a slum in Rio de Janeiro, Brazil, by at least 30 people has once again brought the issue of sexual violence into the international spotlight. Images of the drugged, naked and unconscious girl were subsequently posted on social media, fueling national outrage. But the survivor has spoken about her doubts that she will be able to obtain justice.