Mission 13 | Collectibles Enemy Front Guide
Last update: 11 May 2016
The first secret is lying on the floor, in the corner of the watchtower, which you enter at the very beginning of the chapter.
The second secret is located on a table, next to a frying pan, in a room in the second barracks, from which you rescue a couple of prisoners.
The third secret is located on a stool, in one of the prison cells, in which you find Dietrich.
The fourth secret is located on the table, near the pile of notes and reports, in a secret room, in the commanding officer room - the entrance is hidden, and you must interact with a clock on a bookstand to get there.