Not long ago, claiming to speak with the dead might have gotten Cassidy, the cofounder of the 2-year-old ghost-hunting group Free Spirit Paranormal Investigators, laughed off the stage.
But these days, with no fewer than 11 paranormal reality shows on cable and legions of curious fans flocking to supernatural-themed events, ghost hunting is drifting into the mainstream. And although several 1980s movies featured paranormal professionals - hello, Ghostbusters and Poltergeist - it is now the real-life dramas that are giving ghost hunters a newfound cachet.
Cassidy and a half-dozen Free Spirit members were on hand at Laurel Hill in East Falls to guide guests through the cemetery's biannual ghost hunt, a 5-year-old event that typically draws more than 100 participants.
That night, attendees were just as serious as their guides about searching for evidence of the paranormal.
Toting an electromagnetic field meter (electromagnetic disturbances can signify that an otherworldly presence is nearby) and a voice recorder, Kerry Michael Urda, 45, of Overbrook, paid $30 to wander the graveyard after hours. He conducts paranormal investigations in his spare time.
Trudging toward the grave of Phillies broadcaster Harry Kalas, Urda hadn't seen or heard anything yet, but his spirits remained high.
"It's never too early for ghosts," he said - it was only 9:30, hours before the proverbial "witching hour." Ten minutes later, near Civil War general George Gordon Meade's grave, he paused.
"Did you feel that? I thought I touched a cobweb, but there aren't any cobwebs here," Urda said, examining his hand.
Next to him, his longtime friend Steve Dibartolomeo, 46, of Springfield, laughed. He's gone on several expeditions with Urda, but labels himself a skeptic. "I just like the history," he said.
Standing with a group of about 15 around Kalas' grave, Free Spirit investigator Rami Livelsberger, 35, placed a voice recorder on the ground.
"Harry, are you here with us?" she asked. "The Phillies won today! What do you think of that?"
There was no response - at least none that human ears could hear.
Amazingly, lack of evidence does not discourage anyone - in Laurel Hill or elsewhere.
Popular demand prompted Ghost Tours of Philadelphia to expand its offerings of a ghost-story tour to include a weekly $22 ghost hunt that takes people inside the historic Powel House. The 25-person tours, offered since last summer, have been filling up regularly, said Eileen Reeser, a tour manager.
"They're hoping that something will happen. Of course, we let them know that some nights we'll get absolutely nothing odd happening," she said. "It's not Hollywood. It's not like the TV shows."
Once, though, Reeser said, a group heard footsteps in the empty ballroom of the Powel House. And sometimes ghostly images show up in pictures from the tours, she said.
"You have to wonder - is it a ghost? That's the intrigue," she said.
Ghost hunting isn't generally a full-time profession. The members of Free Sprit Paranormal Investigators are electricians and small-business owners, college students and insurance agents.
L'Aura Hladik, who founded the New Jersey Ghost Hunters Society in 1998, heads an organization of more than 700 members but maintains a day job - like most paranormal groups, the society doesn't charge for house calls.
"I would say the popularity for ghost hunting has always been there, but I think there's an increase in the ease at which one can broach the subject," said Hladik, 46, of Hackettstown, N.J. "There's so many shows on television - it's made it easier. Back in the day, you did everything incognito."
And the number of homeowners willing to phone in a bona fide haunting is increasing, too. In 1998, Hladik and her team fielded three or four calls for help per month. Now, they get 50 to 100 calls a month.
Some, of course, aren't exactly Amityville Horrors.
"Sometimes it's just a shot of WD-40 and the squeaky ghost is gone," Hladik said, laughing.
But some hunts really are bone-chilling. On one expedition, Hladik and her team spent the night in a house where, she said, they saw no evidence but inhaled what smelled like rotting flesh for hours.
When they finally left, they discovered that their equipment would no longer work - the handiwork, Hladik suspects, of an elemental spirit.
"That thing was tracking us as much as we were tracking it," Hladik said.
Even traditional ghost tours that don't involve a hunt aren't immune to the occasional haunting, said Steve Sarachman, founder of the six-member Philadelphia Area Paranormal Society.
On a ghost tour with his 6-year-old daughter and a few society members, the group stopped in a cemetery near a grave.
Almost immediately, Sarachman said, his daughter began to complain about feeling cold.
"I look to my right and see what looks like a little girl bending over a headstone. When I turned around, she was gone," he said. "We went to the headstone, and sure enough, it was for a girl, 11 years old."
While they might sensationalize paranormal investigations, television shows such as A&E's Paranormal State and Syfy's Ghost Hunters (and maybe even Animal Planet's The Haunted, which focuses on, yes, hauntings involving animals) can lend credibility to the ghostbusting set.
But a few late-night viewings of Ghost Hunters do not a ghost hunter make, investigators stress. Maureen Carroll, the public relations coordinator for South Jersey Ghost Research - which traces its roots back to 1955 - said her group requires new members to take six months of in-class and practical training before they're sent out on an investigation.
"People watch the shows, buy equipment, and think they can go out without training," Carroll said. "I say that's like watching ER and thinking you can perform surgery."
And, investigators say, there's something to be said for having a skeptic or two on a ghost hunt.
"They make much better researchers and investigators," said Hladik.
Skeptics weren't out in force for the Laurel Hill investigation, though. Even parents toting their kids said they were open to an encounter with a ghoul or two.
The kids, of course, were almost universally thrilled.
"Ghost hunting is my passion," said Sophia Miles, 11, of Fleetwood, Pa. She's an avid fan of Ghost Hunters and Ghost Hunters International. "I'm not scared."
At the end of the night, although no one had spotted a full-body apparition (what Hladik calls "the holy grail" of ghost hunting), Livelsberger was pleased with the investigation.
"We had a good group - they were interested and excited," she said. "And it's nice to be able to show people the places where stories have been told."