Okay, i believe that Vince is going to kill Lee's brother. I do have facts to back this up, so here goes:
1) Vince in the trailer is seen pointing a gun at someone (could be Lee's brother or parents)
2) There is a picture that shows Vince running away from Lee's families drug store and the zombie of Lee's brother isnt there and being crushed
3) Vince had been arrested for murder so he is capible of killing a person
4) Vince is wearing the same top as he runs away from the pharacy, as he is when he is pointing the gun at someone.
5) His story is first so he would have had enough time to kill Lee's brother/family before Lillys group got there.
This is just a theory so it could just be a load of rubbish.