I've checked around the internet for anything about this, but can't find anything that helps. Basically, I got the Dawnguard vampire quest "The Hunt" from Garan about killing a Dawnguard member disguised as a traveling merchant. I don't have a quest marker pointing the way (which is odd) but the journal said to go to Riverwood.

I can find this damn person at all. I've been all over Riverwood and the surrounding area, there's no traveling merchant that I can find. Never hit this glitch before, any way I can find the guy?