Otho will not share his thoughts on the murder, no matter what you do; it is best to just not ask him about it. This is a relatively minor quest. You only missed out on a level of Restoration and a bit of experience by not completing the quest, so there is no need to start over. Otho's opinion of you doesn't really matter, especially if you have a level of Repair or are far enough to have found better merchants (ie in Ars magicana).
It is relief. I thought Otho shares his thoughts with me. I have 2 level restoration and 2 level of repair. So maybe when I meet the Vampire I still have the chance to confront him... Even if I have not spoke to him? I usually speak with everyone and twice but now my #@#gg mind does not help. It was the start of the game and I reloaded many times. <img src="/ubbthreads/images/graemlins/stupid.gif" alt="" /> So I am afraid that knowing what he was going to tell me skiped him by mistake.
I am <img src="/ubbthreads/images/graemlins/stupid.gif" alt="" />