Unless Ash or Ellen filled her in, Jo didn't know about Sam's powers or that he was connected to the demon. The only thing she heard was that Sam was looking for someone specific who's mother died in a nursery fire like Sams. There was no talk about any kind of powers then, and when she tries to get info from Dean, he blows her off. Sam did talk to Ellen, but Ellen made a point of sending Jo away to get a case of beer. Jo doesn't come back into the room until they are finished discussing. Ellen obviously doesn't want Jo to know what is going on, so for me that rules out her telling Jo anything about Sam. Ash *could* have told Jo, but somehow I don't think he did.

What struck me in Hunted, was what Ash says to Sam. He come back pretty quickly with the info, and when Sam says 'That was fast' Ash says something very odd 'Apparently that's my job...make the monkey dance at the keyboard.' I was struck at how bitter this sounded, and how Ash seemed to be saying he didn't realise it was his job to be everyone's gofer-boy -- which says he is feeling under-appreciated and taken for granted. As he and Ellen were the only ones who knew he was headed for Indiana, I'm gonna have to go with Ash being the snitch. Much as I hate it, it's the only thing that makes sense. While I would *love* for it to be Jo, I think it's just too easy and pat an explanation.