It's the same problem as we find in UFO stories- the stories are short on details, and the descriptions from different accounts are often contradictory. Many devoted christians claim to see manifestations of Jesus, many devoted hindus claim to see manifestations of their own gods, and so on, so forth, with the only common denominator being that these people tend to see and interpret things in a way that agrees with beliefs they already held.
People come forth all the time claiming scientific proof for claims of the paranormal and supernatural, but every time the scientific community at large has looked into such claims, the evidence has turned out to be severely lacking, and very often the findings coming out of these investigations point to outright fraud. Scientific concepts such as electromagnetism can be readily demonstrated on demand, anywhere in the world, using equipment that can be constructed both cheaply and independently on site. Noone has been able to demonstrate the existence of ghosts and bogeymen in this fashion- it's laughable to even think of calling these claims "scientific".