There have always been strange events and there have always been people who are interested in finding out what causes these events. In mediaeval times, much of the work was conducted by members of religious orders. Because of their religious background, their findings often reflected and coloured their conclusions.
Later, with the growth of and interest in science, work was carried out on the paranormal in a clinical, academic way by folk who were highly sceptical of the cause of the effects. Towards the end of the nineteenth century, this work started to coalesce around the science which came to be known as Parapsychology.
In mainstream science, parapsychologists were thought of as people who were engaged in funny science. However, nowadays many of those engaged in parapsychology employ quite rigorous methods to try and identify what in fact is happening.
From all of this comes a third breed of folk with a deep and serious interest in the paranormal. They are the Paranormal Investigator. Although superficially appearing similar to a parapsychologist, a paranormal investigator need not come to the subject from the point of view of the sceptic. Indeed many paranormal investigators are believers.
Parapsychologists usually study the psychological effects on humans when they are confronted with a seemingly paranormal event. Paranormal Investigators examine the wider aspect of such a report including all of the events including the possible psychological effect of an apparently paranormal event.