If laws on this issue don't work...

... shouldn't we think of alternative ways of punishing the rapists, even if rules say it should only be the police and laws to do it, but if there's such a huge problem with most of them just getting away with it, and civilized people feel very strongly that they should be heavily punished for their deeds, shouldn't we be allowed say just to kill them or punish them ourselves somehow?

At least then - there may be less of it and the perpetrators could think that they wouldn't just get away with it even in the absence of effective law enforcement.