In Caps for emphasis. Just because I think this is possible does not mean I think they should get released. There's too much of a risk. Of course a person who once thought murder and rape were OK can change and decide they no longer think that. However, it's too hard to be sure and these crimes are just too heinous. People who commit them should be locked up for life just in case.
If the reason for the crime is an underlying mental health issue, or it was a crime of passion. Those folks can be helped, although they should never be sent back out into the world. They can be healed while in jail, and can perhaps help other inmates as well. A person who kills a cheating spouse in a fit of anger is generally not the threat to society a serial killer is.
Rape and murder are fairly simple acts to describe but when it comes to the underlying reasons there leaves room to absolve some, but not all who commit extremely violent crimes. Many of these people are mentally ill, and many would never do anything that horrible again in their life; it's simply that the law is aware of extenuation, but people, regardless of how responsible they are for a crime, are accountable nonetheless. So some people are beyond help, but some are.
Once you as human accept that everything you do is on your favour or against you, you can realize when you make errors and if you want it you can change but everything has to come from inside and of couse your mistakes can´t be erased but they can be amended and learn from them and become a better person, of course if you want it.
The problem is no one can truly explain what drives someone to commit these heinous crimes. Sure there are precipitating factors, or triggers, but why does someone handle a problem with logic and another with violence? Whether its a genetic flaw or environmental conditioning or a loose connection there is no way to determine the why. If you can not determine the why, then how can we state that the individual will not do it again? How can you hope to rehabilitate when you do not know the cause? I do not believe there is any hope for rehabilitation. Temporary remission, maybe, rehabilitation, no.
It would vary from circumstance to circumstance. The first question would have to be, were they innocent in the first place? If they were wrongfully convicted of a violent crime like this, or there were extenuating circumstances (like self defense, or a female that was having an affair) then I would have to say they could be rehabilitated. For the group of people who do this in premeditation, I don't think there would be a day in their life, after the event, that they didn't think about the whole scenario. They know what frame of mind they were in, and they should suffer the consequences. They have scarred themselves for life.
After raping or killing innocent people for your own sick reasons you are not a person you are a monster and you have no rights or quality of life and we should not waste time and money on your well being. Rapists and killers don't deserve to be rehabilitated. They can't be.