Recently, I was in Minetown and was attacked by some sort of monster that caused me to begin hallucinating. Without noticing this fact right away (I'm still adjusting to a new user interface), I accidentally attacked what turned out to be a watchman. I don't know whether or not I actually killed him, but I received no "you murderer!" messages. (I don't know whether hallucination affects that message's appearance or not, though).
In such a situation, is there anything one can do to get the guards to forgive you? What about angering the town watch through other means (vandalizing, theft, breaking and entering) -- are those treated the same way as well?