One of the reasons Allah (swt) forbade alcohol. Not saying that things like this don't happen without it, but it may have made the whole thing worse.
Narrated Anas: Allah's Apostle said, "Help your brother, whether he is an oppressor or he is an oppressed one. People asked, "O Allah's Apostle! It is all right to help him if he is oppressed, but how should we help him if he is an oppressor?" The Prophet said, "By preventing him from oppressing others." [Bukhari]
Gee, you think that would include stopping him from raping someone?