Nibblers...?

The Mom: "There's a hole in the litter bag!"

The Hubby "Someone nibbled!"

Chili Bruce: "Not Me!  Look it, I'm all snuggly and sleepy here!"

Manny: "Don't look up here!  I'm just minding my own beeswax."

Voiceover: "A mysterious case of evidence, with no proof!  The humans claim that it must have been a cat, but the cats won't admit any wrongdoing, and think that the humans had better watch it!  Could be another unsolved casefile."