First post on this sideblog - been lurking for a while but it's almost impossible to incorporate such specific DID content into our BPD blog. I don't have an article or previously-written post to cite, since I typically gravitate towards clinical research & couldn't find any that specifically address intentional internal death.
That being said, my therapist has been working with DID clients for well over a decade, and keeps up to date with her research extraordinarily well. When I asked her an iteration of the Murder Question, she explained that "killing" an alter, permanently silencing & disabling them, isn't technically possible. That which exists in the subconscious exists symbolically, not literally. Without permanent brain damage, effectively an ultra-precise partial lobotomy, which would still effect other aspects of a person's functioning, completely killing off a segment of one's brain is impossible.
What would be possible is to force an alter into an indefinite state of dormancy, essentially a coma. This could, theoretically, be performed symbolically by another alter, but as innerworld activity is nothing but visual rationalizations of the subconscious, it would actually be a function of what the entire system needs to survive. That means one function of identity & the self would be put on hold, but could be "resurrected" at any given time to reassume its assigned duty as the brain sees fit.
As opposed to the intentional banishment of a particular alter, helping them to understand their place in the system will always be healthier. Remember, every alter was created for a reason & every alter is a part of you. Even if that reason seems malicious, masochistic, maladaptive, harmful, your brain had some reason to believe that it would keep you safe at some point in time. Not just you, but all of you. That which seems malignant often needs re-healing. Focus on redeeming persecutors, whether they're the ones threatening murder or under threat of being killed. Unifying the system to a point of core functionality often starts with them.
Something else to note, since I've heard it infrequently mentioned, is the possibility of one alter symbolically "killed" by another in an act of sadism, rage, or purification, who then "reincarnates" into another form. Obviously, again symbolically, this radically & violently transforms an aspect of the self into another form. The core identity of that alter remains intact, but they may take on the appearance of something else, a ghost, an angel, a dog, to represent a change in how the whole self views its part. I would think that this generally falls in line with how that particular alter is treated within the system, if not externally as well.
Last possible alternative is fusion, or re-absorption. While most think it's impossible to fully reintegrate all parts back into a single identity, "fragments", or semi-formed, half-baked, unarticulated pieces of alters that splinter off of the pre-existing ones often don't last too long in a system before the brain recalibrates and simply adds those newly-learned or newly-adapted traits back into the already-integrated system from whence the splinter came. So in a way, this could be looked at like an Athena-esque birth & death, I guess.
Source for Persecutor & Fragment descriptions here (w their own sources listed @ bottom of page)
TLDR; no, literal death doesn't exist in the figurative headspace