David's Files are secret files belonging to David Madsen that he gathered during his investigation on the Dark Room Conspiracy.
Max can find a binder of David's secret files in his garage, which include pictures of Kate Marsh. She can also discover that David installed hidden cameras inside the Madsen Household.
Max investigates David's laptop and locker. They reveal that David is behind Rachel for some time. David has a map for locations of security cameras for Blackwell Academy and Pan Estates. With the help of David's investigation, Frank's Logbook and Nathan's phone, Max is able to track down the Prescott Barn, which lets her find the Dark Room and Dark Room Victims.
Photo 1 from David's garage files
Photo 2 from David's garage files
Photo 3 from David's garage files
Photo 4 from David's garage files
Rachel Amber profile from David's laptop
Kate Marsh profile from David's laptop
Max Caulfield profile from David's laptop
Clue 1 from the investigation board
Clue 2 from the investigation board
GPS sheet 1 from the investigation board (Jefferson
GPS sheet 2 from the investigation board (Nathan
GPS sheet from investigation board (Chloe
GPS sheet from investigation board (car owner unknown)
Blackwell Campus map with security camera locations
map with red marks, which probably represent security cameras
David's record of Kate's actions.
Photos of Max are also featured in the investigation.
Unknown car license plate.
Jefferson's license plate.
A map of Arcadia Bay with the GPS coordinates by reddit user /u/libbysthing