There are two guys outside the tavern in the first city. One of them is a guard. I'm helping him out to find out if a certain NPC is carrying out illegal activities. He told me to get information about him by asking to other NPC's.
It would be great that if an NPC doesn't know about the person, at least say something like "I don't know him". However, NPC's responds as though you have worded the sentence incorrectly, in other words, they dont understand you.