County Jail
Follow the mission walkthrough up until you crawl through the first vent. Instead of crawling through the vent, hit the checkpoint and go through the door into the main office of the police department. There will be rows and rows of desks with a bunch of officers here. You want to make your way from one desk to the next and then turn as the room turns. The evidence is in this smaller are of the room on one of the desks.
Outgunned
The evidence for this section is down in the parking lot on a stack of boxes. Find the gate that leads out to the street on the left side. Put the nearest truck between you and that gate. The evidence should be on a stack of boxes nearby.
Burn
You can find this evidence pretty easily by following the mission walkthrough. It is on a crate a little ways before the exit from the warehouse.
Hope Fair
As you make your way along through the fair, you'll come to a long street filled with stalls. The evidence is on the right side of the street near the intersection just before the exit. It should be near a truck on a stack of boxes.
