Bloody message (tentative) is a file that can be found in Resident Evil 7 Teaser Demo: Beginning Hour. If the player reads it while having the Blank Notebook in their inventory the it will turn it into the Old Notebook and writing will appear in it.
The file can be found in the attic on the wall next to the TVs.
"Five guests murdered, but where is unknown. Nothing to point to their final gravestones."
- The file acts as a hint as to where to find the bodies.