I am, for various reasons, attempting to murder Ondolemar and his Thalmor Guards in Skyrim. I have also murdered multiple vampires disguised as normal merchants in the past.
However, I keep on running into problems. Even if I am completely undetected during the murder and gain no bounty, the guards turn violent against me if I approach them. They do not attempt to collect any bounties. Something like this is listed in the bug section of the wiki, but I am not completely sure that this is a bug/the same bug.
If I am slightly detected after killing someone (eyes slightly open), I get a bounty of 1000. This is the case even if no one detects me fully.
I understand there are ways to kill Ondolamar without getting too much of a bounty. I can cast frenzy on him, for example. However, I wish to kill him with sneak if possible. How does the murder detection system in Skyrim work?