Mary Marshall's investigation kit isn't filled with the usual tools.
There's the Mel Meter for measuring electromagnetic fields and temperatures, the KII for analyzing frequency types and the laser grid for detecting shadows and visual disturbances -- just to name a few.
She demonstrates each to a class of Harper College students either intrigued by or hoping to pursue her profession: ghost hunting.
The paranormal researcher and investigator, together with a doctor of anthropology, is spending the semester teaching the continuing education class, Paranormal Investigation: A Global Perspective.
"This isn't hocus-pocus, but rather getting proof of the what, where and why in paranormal activity," said Marshall, who's known as the Paranormal MD. "There's a tight correlation between solid science and what we're trying to do."
Marshall lectures about demons, possession, portals, Ouija boards and the human realm. She plays recordings of electronic voice phenomenon captured during her investigations.
In one, something sounding like "excuse me, Mary, I'm here" comes through, causing some in the class to get goosebumps.
Meanwhile, cultural anthropologist Scott Cashman provides an overview on the role of spirits across the globe, including the growing popularity of ghost hunting in the United States. Ghosts in certain parts of Africa, for instance, are believed to cause illness.
"The belief in ghosts or spirits exists in every part of the world," he said.
About 40 students signed up for all sorts of reasons.
Jerry Seiling of Palatine said he's a paranormal investigator who has gone on several ghost hunts but wants to learn more. Marshall hopes to teach people like him how to develop their investigation skills, including the use of equipment, software and the evidence review process.
Seiling said he's had several personal encounters with ghosts, including last year at his son's apartment in Palatine.
"Things started going crazy in the living room, and the blind near the patio rose to a 90-degree angle," Seiling said. "And my grandchild sometimes saw a little boy, even though we couldn't see anyone."
After doing some research, they discovered a double murder-suicide had taken place nearby in 2004. They believe what they experienced was connected to the crime, in which a 27-year-old father fatally stabbed his wife and 4-year-old son and then himself.
Another student hoping to learn more about spirits is Ingrid Rapa of Palatine, who believes her recently deceased father tried to communicate with her family while they were cleaning out his Florida home.
"It was 90 degrees and the air was heavy and still, but all of a sudden the boat cover went flying off," Rapa said. "It was just so strange, but I believe it was him."