There are 39 collectibles for this achievement. You can use the walkthrough to find the exact locations.
News Article #1 - Apartments
Warning Poster - Apartments
K. Douglas Personal Info - Police Station
K. Douglas Police Progress - Police Station
C. Nelson Personal Info - Police Station
C. Nelson Police Progress - Police Station
A. Grace Personal Info - Police Station
Status A. Grace Police Progress - Police Station
G. Soderberg Personal Info - Police Station
G. Soderberg Police Progress - Police Station
Missing Persons Report - Police Station
Witness Description of Clothing - Police Station
Suspect Released - Police Station
Killer's Profile - Police Station
Map of Killings - Police Station
Spray-Painted Graffiti - Cemetery
Tabloid Article #1 - Asylum
Tabloid Article #2 - Asylum
News Article #5 - Asylum
News Article #6 - Asylum
Tabloid Article #3 - Asylum
Poem 1 - Judgment House
Poem 2 - Judgment House
Poem 3 - Judgment House
Poem 4 - Judgment House
K. Douglas Cause of Death - Town
K. Douglas Family Photo - Town
C. Nelson Cause of Death - Town
C. Nelson Family Photo - Town
A. Grace Cause of Death - Town
A. Grace Publicity Photo - Town
G. Soderberg Family Photo - Town
Chalk Bell Symbol - Town
Baxter's Official Comment - Town
News Article #2 - Town
News Article #3 - Town
News Article #4 - Town
Witness View of Eyes
Witness Trauma Report