Unfinished Expedition

[Taddy Mason]

how do i complete this quest? the 3rd set of document i need to find is inside a building with no entrance, so i can't reach it.
I took a screenshot in case that helps. Anyone else try to do this mission and get similar issues?
https://steamuserimages-a.akamaihd.net/ugc/2535046873937931381/DF3FBC16225B5005AA558572EB495063433BC6BE/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

[_Ki_]

On the side of the building is a picture broken in two, position your self so they line up to reveal a way inside.