Board Thread:General Discussion/@comment-60.229.180.168-20131010063530/@comment-24261859-20140102035923

There is an odd glitch where if you kill someone while hidden, you won't get a bounty, but if anyone saw the victim die (i.e., you killed them from a distance), eveni f they didn't see you, you get a "partial" bounty, so to speak, where certain NPCs with an agressive reaction to crime as part of their AI data will attack you on sight. This happened to me where I stealth killed a "Visiting Advisor" as part of a Dawnguard quest. I was hidden and thus did not get a bounty, but one guard who saw the guy die somehow knew that I was the culprit and attacked me. I was able to kill him too without bounty because he attacked first seemingly without being provoked, since the crime system did not register me as having committed the act.

Also, when I sniped a Thalmor Justiciar, the same thing happened where one guard who saw her be killed but did not see me started treating me as if I had that 1000 gold murder bounty. Some other NPCs (Elrindr too, which matches your story) were hostile as well.