Nor do I, but I wouldn't discount the possibility from a simple creature.

[ No, Break just hates Cheshire... Don't actually listen to him. ]

But it's more likely that it was intentionally removed, but that's strange too. I can't think of the cat removing it for anything but a very good reason, and at least so far as I know, none of the suspects would exactly know the significance. Even if they did, it'd be useless to them.