As they painstakingly pore over the data, the team separates fantasy from reality to offer clients some kind of explanation.
"You have to take shreds of science and technology and put them to work for you and see what works," said Wilson.
Often they learn that a flickering light isn't a ghost but a bad switch or a room isn't haunted but contains hallucination-inducing unshielded wires. Other times, they have no explanation.
"There's a lot of weird things out there that we can't explain," said Hawes. In one investigation, they observed a 9-year-old girl, seemingly possessed, with the strength to lift objects too heavy for most adults. In another, they encountered a person pushed up a flight of stairs ostensibly by an invisible force.
But even when they find mundane explanations for extraordinary claims, they say they gain something.
"Every case is a learning experience. We're happy if we find something or not. We learn something for future cases," said Wilson.
And patience, it turns out, is it a critical trait for aspiring paranormal investigators. Though tracking ghosts and spirits sounds glamorous, devoted hunters acknowledge that the work can be tedious.
"It's really boring," said Cheri Esperon, 38, founder of the Northern Alliance of Paranormal Investigators in Kenosha, Wisc.
Some investigations involve listening to recorded white noise or sitting in an empty building for hours on end, waiting for something out-of-the-ordinary to appear.
"For a lot of people, the reward is late in coming," she said.
But Esperon, who is an office manager for a local church, said that what led her to start the group -- and what keeps her hooked -- is "morbid, rabid curiosity."
She said she'd been chasing urban legends for years but, after seeing Syfy's "Ghost Hunters," decided to come out of the "paranormal closet." She now works with about a dozen other investigators on roughly two cases a month.
They end up debunking about 65 percent of their claims, she said, but the remainder is enough to drive them forward.
"I don't have the answers yet, every answer I get gives me another question so I keep going," Esperon said.
Though these investigators say they employ the scientific method and critical thinking in their craft, seasoned skeptics say the results speak for themselves.
"You have literally hundreds of groups in North America that have done tens of thousands of investigations and yet none of them are finding anything definitive," said Benjamin Radford, managing editor of the Skeptical Inquirer Magazine.
Radford said he doesn't dismiss ghost hunters and has even investigated reported hauntings himself, but he said, "If you're going to do it, do it right."
Sound science requires sticking to a process based on gathering empirical, measurable evidence, not picking and choosing the pieces that most support your case, he said.
In one case he investigated in a Santa Fe, N.M., court house, a deputy saw a mysterious white glowing figure on surveillance camera footage.
The mysterious figure made headlines as locals circulated stories about resurrected Native American spirits from a nearby cemetery.
But after four days of haunting the court house himself, Radford discovered through trial and error that the "ghost" was actually an insect caught on camera in the morning sunlight.