Just look into the camera and say, "I see you". Then start laughing like a maniac for 20 minutes and if someone is using it maliciously, I guarantee they will stop. They might even start going to church again.
not sure about the sim but im pretty sure if you open task manager you can track if your pc have high usage and what process is causing it (i.e. activated camera). It also helps to run scan with more than 1 AV (do not use more than 1 AV installed at a time). make sure you do your scans under safe mode (w/o networking)