Outside the main building, in a little alcove just next to the stairs.

Inside the main building.

These two checks are right next to each other on the top of the main building.

This check is only accessible from the rooftop, by rolling on top of these cargo containers. It's advisable to look before leaping, as this can be slow to return from.

On top of the truck-side scout tower. This check is visible from most of the map.