we had one coming into our sunroom through the cat door to eat the cats' food.
the mess he made there is what tipped us off to something, so i put a cam there
and caught him in act the very same night. turns out they are clever enuf to
claw open the 'normal' magnetic-lock cat door, as it doesn't lock from the inside.
I replaced it with a dual-scan RFID model, so now the cats don't even need collars
(it detects the RFID chips embedded in their neck) and since it locks both ways, our masked
bandit can no longer make a mess in the cat room...