Why do American/Canadian police interrogation rooms have such weird camera angles?

Always bothers me when I watch real life footage of questioning of suspects in documentaries.

This is such important moment. If person is guilty - this footage would be viewed by court. And you practically can't see anything!

They put ONE camera UP HIGH. When you basically just see silhouettes. You don't see EMOTIONS of suspects and victims. And this is very important. Why not put additional camera in front of person and at least lower? They even have mirror and room behind it.

Even in crime tv shows they pay attention to that aspect and their "recording cameras" at good angle. But not in real life interrogations rooms.