I'm a Catholic aswell, I do believe in Heaven and Hell, also in ghost, I just think that you can only become a ghost if you weren't being buried properly, my grandma was murdered while she was in the grave yard working, she was murdered by some people, 40 years later, her body was found, but the only thing that remained was her body and head, it was my dad's mother, that why I had to go oversea. If you go to Vietnam, and visit the graveyard at 12AM or late, you'll see ghost, if you go further away from light, residents would tell you story and they are scary, when they explain it, sounds creepy, usually I'm not that scared when stories are being told by my friends, while I was in Vietnam, my relatives and my family went to visit my uncle, his mother was buried in their backyard, sometimes you would see a white glowy ball, they are the protector, they protect the residents in the house from any dangers.