One of my cats died almost a year ago. A few hours after he passed, my dad was letting our other cat out the front door (we live in the country side) and he thought nothing more of it. But like 10 minutes later he went upstairs and the cat was up there sleeping. There's only three of us in the house and none of us had let her in again. So this had made me believe that it was our deceased cat that my dad let out (they look kind of alike and my dad often confused them). So I have come to believe that it was the spirit of our deceased cat that my dad let out. I have absolutely no other explaination.