I didn't get to read the posts but this dream can be interpreted in many different ways. I found 3 of them:
1st A Dream of Fear of What's Happening in Our World
It seems as though your fears have somehow interfered with your dreams. I am not sure if you are actually single/living alone but you have heard about a serial killer in your waking life. If this is the case, then there is the very real fear that someone could be living so close to you that is a murderer. This is something we live with daily. It could be that you are wondering just how safe you really are. The murderer when you meet him seems to be a very "normal" person. Of course then you think if he's "normal" the rest of the world thinks this too. Could we have actual knowledge of something criminal going on and not get the support we need?
2nd An Intuitive/Prophetic Dream--Something To Think About
Being you have knowledge of this actual case. Is your intuition heightened to the degree that you are picking up on the reality of this murder case? Perhaps you are. Maybe you should monitor this case to see if the events unfold the way you have dreamed. This means, maybe the murderer does kill women who he/she considers a whore. Maybe the murderer does live in a very nice apartment complex.
3rd A Combination of Things
Digging underneath the surface of the dream, ruling out the obvious and premonitions, perhaps this is a dream of fear borne out frustration for you.
To share a space like a bathroom with someone denotes intimacy and closeness. If one is not careful though, it can be invasion of privacy. Think about it, this isn't your bedroom--it's your bathroom! The toilet flushes away the ugly and the garbage. We shower and bathe to make our selves cleaner and presentable to the world. We brush our teeth to taste freshness and rid the foulness that prolonged sleep brings.
Sharing a bathroom is always an annoyance, however, this is something you can deal with if you feel as though you can feel safe and trust the people that you are sharing with. Even when the door is broken, you are left vulnerable but will deal with it until you discover this is a person that cannot be trusted.
The authorities and management we trust to make us feel safe in this dream have failed you so you can only rely on your own instincts to make sense out of what has happened to you.
In a nutshell, somewhere along the line someone or something has made you feel vulnerable and exposed---therefore unsafe. Once you communicate with the killer in your dream--he hears of your dissatisfaction, he moves further away to make you feel better.
Seems like your frustration and fear, can be eliminated through communication---or for a certain situation, there will be a resolution. It also seems like once you fully investigate something (get to know the murderer), you'll realize you're not the target at all for whatever it is that has you frustrated.
These are just a few interpretations. Hope this helps you!