Sometimes you can be certain it's one culprit, and it turns out to be another. My dog Heather used to shred paper, especially Kleenex. I caught her red-pawed on more than one occasion. Heather passed away, and a few months later I started finding shredded Kleenex again. I admit to wondering if Heather's ghost was doing it. I eventually caught my Siamese happily shredding the tissue. Now my toddler shreds Kleenex too. Thanks, Mr. Mumbles for being such a great role model!
I had one cat deliberately do what had gotten the other cat in trouble. I am certain she was trying to implicate him. His punishment involved being ignored for a day. I needed my fur fix, so she got 2X the attention while he was punished.