We've found more signs of illegal surveillance embedded in the walls by our back door, as shown in the photographs below. This time, the area that gives off strong radio frequency (RF) signals indicative of a hidden camera or microphone is right next to the door and about halfway up.
After I photographed this, I attempted to remove it by grabbing the part protruding from the wall with a tweezers and pulling on it. A small brownish crust similar to the one I removed from the leg of my bed as explained in an earlier post broke off and was so thin that it was crushed into tiny pieces. A small grayish area that's slightly recessed remains on the wall, and this appears to have a hair-thin fiber optic line in the center, although it's so small that it's hard to tell for sure. The area still gives off strong RF signals, so the stuff I removed must have been there to hold something in place.
The wall this pinhole is on intersects another at right angles a short distance away as shown. On the opposite side of the intersecting wall is a built-in cabinet that has clear signs of tampering at the back of it: the back of the cabinet has been removed at some point and then both heavily glued and crudely screwed back together so that in order to get to the illegal equipment sealed inside, one would have to either destroy the back of the cabinet or cut a hole in the wall itself.
I assume the embedded item is a camera, since it's positioned in a way that gives a view of the entire length of our downstairs hallway and looks directly at our front door.