Well, right after i watched s06e06 episode i was thinking that the shoot wasnt from Jane's gun. I believed that one of the two guys with no tatoo would have shoot him by the back. Maybe RJ doesnt have the tatoo.
So my suspect was Ray Haffner, because he would fit better, in physical matters.
But after watching the promo i don't know what to think... maybe is the Sheriff because the other two looks more like employes, always calling someone to give some news.
So now i go with the Sheriff Mcallister