I recently had a discussion with someone who writes ghost stories. He will take his inspiration from genuine locations and people, then write a fictional tale. He told me that some times he just changes the location and people around, so his stories are good for anywhere and he has spent years spreading them around.
It has made me wonder about some of the older ghost experiences and how much of what we know is fact or fiction. By taking what we know about ghosts from investigating them and comparing them to older claims of hauntings, can we identify potential genuine cases and frauds? Do ghost stories had certain identifyable motiffs, such a ghost coming back to show where a treasure is hidden?