By Chaka Ferguson
The Associated Press

On Halloween, when legend says disembodied spirits return in search of living bodies to possess, Joe Nickell goes on the prowl, too - for ghosts, ghouls and other things that creep in the night.

The former private eye, who used to solve arsons and theft rings for a security firm, is now a senior research fellow at the Committee for the Scientific Investigation of Claims of the Paranormal, or CSICOP, in New York.

His job: unravel the unexplained, debunk the deceptive, unmask the hoax.

Nickell, 58, joined CSICOP in 1995 after a career that also included stints as a professional magician and professor of English at the University of Kentucky.

CSICOP, based in Amherst, N.Y., encourages the critical investigation of paranormal and "fringe-science" claims from a scientific viewpoint.

Nickell says he has investigated some 40 cases of paranormal phenomena, such as ghost sightings and alien abductions - without finding a smoking ghost, so to speak. Although still fascinated by reports of the supernatural, he says he's found no credible evidence to support its existence.

"The question is whether we can find evidence that makes up for the unlikelihood of ghosts based on everything we know about science and nature," he said.

In his 2001 book Real-Life X-Files, Nickell writes that many of the claims he investigates are hoaxes, and others are simply hallucinations or anomalies that can be explained naturally.

All of this makes him a killjoy of sorts for the 38 percent of Americans who believe in ghosts, according to a 2001 Gallup Poll.