This story is interesting and inspiring. The writer lost his wife to a rapist and murderer who basically fits the 'lone rapist' idea. But it made him want to make the point that usually this is not at all what happens, that if your assumption is that the fellow who's going to do people harm is some OTHER, some MONSTER, you're working from wrong ideas that won't help you; that we need to confront that it's all of us, it's the guys next door, it's people in your workgroup, who do the violence that we see every day.
Also of interest was his point that folks would often tell him they hoped the perpetrator would get raped in prison, and how that struck him as wrong, as requiring a kind of infinite loop of rapists to punish each other.
Found, of course, through the ever-awesome Metafilter.