My cat has been peeing in the toilet for god knows how long?

I'd noticed that someone had not been flushing the toilet in one of our bathrooms. All of the family members claimed to be flushing. I'd also noticed that the cat box was suspiciously clean (with the exception of feces). I suspected that she may be using the toilet, so I set up a video camera and let it run overnight. The video footage revealed that she was the culprit who was going in the toilet but not flushing. She apparently started doing this on her own.