Chapter XIV - Secrets - Ray Call of Juarez: BiB Guide

The first secret is located in a room which you will enter right after leaving William's cell.

The next one is located nearby the previous one, in much bigger room with some columns and with big metal gate (next to it).

The third secret is in a chest in a room without a roof with many tables (in a corner).

The last but one scroll is hidden nearby the previous one, in the second room with the double door. From that moment you will start follow William.

The last one is in the first room covered with the water (in sewers).