Can murderers change – or are they born 'evil'?

> And since they can not ever shed that dark passenger they can never be let back into society again.

Words written by someone still sufficiently (and blissfully) ignorant enough of their own dark passenger they can still write these words.

May you one day learn why those words are so deeply ignorant… may and everyone survive your meeting your dark passenger(s).

Everyone can change; most don’t want to.

Murder requires premeditation, so that precludes self defense. The two parts are: The killing of someone without legal justification (such as self defense), and the premeditated plan to accomplish it. There is something called "mens rea," the guilty mindset, that informs the court of guilt or innocence.

This will get you into manslaughter and other shades or degrees of killing, too.

The rest of what you said, I generally agree with. If you believe someone with a mental condition can sometimes "come around," then you'd also have to believe that someone who killed because of a DSM-5 defined condition that lists it as a symptom or hallmark can be cured of the triggers that made them do it. But I'm sure in most cases that privilege has to be long fought for.

I always thought the Biblical command should have been "Thou shalt not murder" since it is absolutely possible to kill without even a trace of mens rea. Auto accidents are a good example. And war killing in the Bible, as in modern life, isn't considered murder either (Geneva Convention subjects aside). There is legal justification.

By way of expanding upon my comment above...let's try to remove ethics and morality from the discussion.

All animals that live in groups have 'rules' that protect the group from behaviors that threaten the group's existence. A group member who behaves in an way that threatens the group itself, is shunned, ostracized, or killed.

Human society is no different. During relatively modern times, we have adopted written rules of behavior with procedures to judge and punish violators to the extreme of imprisonment and even death.

And prison populations throughout the world are overwhelmingly male. Further evidence that there is almost certainly a biological/genetic factor causing males to behave in a manner resulting in society imprisoning males at a much higher rates than females.

To be clear, it is also very true that only a small percentage of males are ever charged with criminal (anti-social) behavior. So, there are obviously other factors involved beyond just being male. However, that doesn't change my point that genetic traits almost certainly play a role. There is a huge body of science that has been studying human anti-social behavior for centuries.

I mostly agree; however, biological/genetic factors do not control everything. They may be involved in such traits as aggressiveness etc, but I would think that even these traits are not certain and can be changed (by many things, including your own ideas, but also many kind of external factors), and this does not include such things as "evil" and does not directly include "murder" (although it can be included indirectly, since it is related to things which are more directly affected by genetic factors, which can end up with such things). There is the question of exactly which things the biological/genetic factors affect and how much, and scientific experiments may be able to figure out some of these such things.

Regardless of that, it does not mean that no murderers can ever changes (although some might not change as easily), that genetics can predict if you are a murderer with 99% accuracy, that sex or gender can predict it with 99% accuracy, etc. But, it does mean that it can have a statistical effect.

Exactly

I would think that it may be possible to be born with a greater or lesser disposition of aggressiveness and other stuff, although "evil" isn't one of these things. Furthermore, these (and other) things can change due to anything (experiences, situations, etc), and do not apply directly since any situation will be different.