Pacifism is the opposition to war and violence. Most pacifists propose to abolish the army, such as Costa Rica and a small number of other nations have done. Some also propose to abolish the police. In this case, how do they propose to address violent crime?
Frankly, the only seemingly well-explained example I found of a pacifist openly discussing the topics on the web (interview with Tripp York, who is a pacifist from Christian standpoint and an author of "A Faith Not Worth Fighting For: Addressing Commonly Asked Questions about Christian Nonviolence" from Cascade Books), the answer really was... no answer.
When someone asked whether in practice, pacifists merely "outsource" the violence to others (e.g. call the cops), his response was that (1) Yes, that is true, and (2) His personal solution to that was "gardening". No elaboration was produced on what happens if his family is threatened while gardening - would he NOT call the cops?
The same vague approach abounds. For example, when asked about Hitler, his response seems to be summarizable as "you should speak out, and if necessary get arrested" (presumably, protesting). How such an approach would have, in any way, shape or form, stop Hitler, is left unaddressed. He also quotes, ironically, Malcolm X.
The interview did point out several books which may contain deeper answers, but if those books contained better answers, he surely would have referred to such. "What About Hitler" is one.
One a more serious note, radical pacifism seems like an implausible approach from game-theoretical viewpoint. It's inherently an unstable strategy. For an example of a great explanation of why, we need look no futher than the classic "Selfish Gene" by Richard Dawkins - in "Aggression: stability and the selfish machine" chapter he models pacifist (he calls it "dove") strategy, and concludes that it is not evolutionary stable - a small minority of hawks (aggressive violent strategists) have a tremendous advantage. Given that human society, as a rule, contains at least 1% psychopaths (source: DSM-IV), pacifism (complete rejection of violence) as a global solution simply can not work - without more nuanced strategies employing aggression, psyhopaths (hawks) will propagate and win till there are ~ 1/2th of population of them. In other words, anything proposed as a solution by radical pacifists is unlikely to actually work in current reality.