Location Found: Inside Gabriel's hotel room.
Used On: The other residents' possessions to grab their fingerprints.

Grace's Sketchpad

Location Found: Starts in Grace's inventory.
Used On: Emilio's doodle in the dirt. It's also used on the symbols on Montreaux's robes.

Tube of Suppuration H

Location Found: Inside Lady Howard's bathroom.
Used On: The Abbe's office window so Gabriel can open it and enter the office.

Coordinate Device

Location Found: Mosely's bedroom under his clothes on the floor.
Used On: The sites discovered through the Le Serpent Rouge to mark certain areas.

Map

Location Found: Madeline Buthane's room inside her bedside dresser.
Used On: Grace's laptop and scanned into SIDNEY.

Two Parchments

Location Found: Lady Howard's bedroom by searching the bed.
Used On: Grace's laptop and scanned into SIDNEY.

Manila Envelope

Location Found: Taped on the outside of the museum door.
Used On: Opened to discover Le Serpent Rouge.

Le Serpent Rouge

Location Found: Inside the manila envelope taped on outside of the museum door.
Used On: In conjunction with Grace's laptop to discover important locations.

Bloodline Manuscript

Location Found: Dug up behind Larry's house after he buries it. Also, it's regained from the orange rock after Buchelli buries it.
Used On: Given to Prince James.

Emilio's Doodle: SUM

Location Found: Emilio writes the word "SUM" in the dirt on the second stop of the tour group at the top of Blanchefort.
Used On: Must be scanned into SIDNEY to solve a Le Serpent Rouge puzzle.

Postcards

Location Found: Grace purchases three postcards from the museum during the final day.
Used On: Must be scanned into SIDNEY to solve some Le Serpent Rouge puzzles.

Gabriel's Talisman

Location Found: Starts in Gabriel's inventory.
Used On: The demon creature's head to startle and stun the creature.

Gabriel's Dagger

Location Found: Starts in Gabriel's inventory.
Used On: The demon creature's throat.

To GameSpot