The file can be found in the attic next to the telephone.
Resident Evil 7: BiohazardEdit
The file can be found in the radio station in the Swamp area.
"Are they watching us from that helicopter?"
The helicopter in the photograph features the Umbrella logo on the fuselage. The intention for including the file seems to be to encourage conversation about what the final game's story could be, as the file itself could be interpreted many different ways.