When I killed her she jumped over to a building to the right, Her left. I Found out how to get up to the first building thanks to Joe. The second build I got up on by NOT jumping over to it Directly. but going around the Invisible wall.
At first i tried to jump over to it. But was stopped by the invisible wall there. I Got back up to the first Building she was on. then walked over to the end of it and jumped over to the roof of the second building. then jumped down. Boo for invisible walls in wrong places
This is from Joe
With a little help from what's basically the same question at GameFAQs, I was able to figure it out.
As their instructions are a little confusing ('across the street' and any of the cardinal directions mentioned are flat out wrong), the working instructions are:
From standing in front of the building, facing where the Sheriff had been.
Turn to your left, and go to the neighboring building.
Just past the building will be some crates; jump up those.
On top of this building is a sign with two diagonal braces; walk up one of the braces.
From the top of the sign, jump over to the next level of the building.
Walk out on the rod heading towards the Sheriff's building
Jump off the rod before it becomes a cable.
It's actually relatively easy, once you figure out that you can walk up the sign supports. (I had originally tried jumping onto the sign directly)