Tommy Mullen, 39, peers into the dark on the third floor of the Marcus Daly Mansion in Hamilton, hoping to hear or see something out of the ordinary. Motion lights from the backyard cast eerie shadows down a nearby hallway. The house moans occasionally, the wood walls and metal pipes settling in the cold February air.

"If there's anyone in here with us, we want you to know this is your house," Mullen says, his Arkansas accent making him sound oddly like Matthew McConaughey. "We don't want to intrude. If you'd like to talk to us, or if you'd like us to leave, please make a noise."

Silence. One of Mullen's fellow paranormal investigators slowly pans across the room with a digital camcorder, watching the night-vision feed on the LCD screen.

"We just want to communicate with you," Mullen pleads, glancing down at his electromagnetic field meter. The light is green. Translation: No ghosts.

• Photo by Alex Sakariassen
• Tommy Mullen heads a group of paranormal investigators in Hamilton. The group, Hawk Paranormal, recently hosted a public investigation at the Marcus Daly Mansion. The event turned up zero ghosts.

Then Mullen hears a faint whisper. It grows louder, becomes several whispers, and adopts a steady crunch.

"It's one of the other groups crossing the yard," Mullen says, his concentration broken. "Can someone tell them to shut up?"

Mullen and his crew at Hawk Paranormal, a Hamilton-based paranormal investigation firm, aren't used to dealing with large crowds. More than 20 people arrived at the Daly Mansion Feb. 6 for a seminar and all-night guided investigation. This could be the first in a regular lineup of ghost tours at the mansion hosted by Hawk Paranormal. Mullen says such events could be a great way to use the growing popularity of shows like SyFy's "Ghost Hunters" and the Travel Channel's "Ghost Adventures" to gain some community exposure.

But tonight, he's probably sacrificed any chance of gathering strong evidence of paranormal activity. "There's just too much noise to collect audio tonight," Mullen says. "This isn't what I typically do on an investigation."

Mullen's not trying to prove anything to himself. He's believed in ghosts since his first encounter with one at age 7, during a night at a family friend's house in Arkansas.

"I heard a noise late at night that woke me up, like someone coming down the stairs," Mullen says. "Walking across the room was a lady...She just stood at the back door, put both her hands up on the doorframe, and started standing there like she was staring outside. Then she disappeared."

By age 17, Mullen had developed an interest in ghost hunting and started conducting solo investigations at cult ritual sites and abandoned houses around Arkansas. He says his main goal back then was to prove to himself that the paranormal wasn't just a bunch of bunk.

"I've done that," he says, more than 600 investigations later. "I've proven to myself that something else is there."

Now, he says, it's a matter of convincing the rest of the world.

Mullen moved to Montana five years ago and set up Hawk Paranormal with a few fellow investigators. His crew now consists of eight, including one skeptic, and they regularly search private homes and historic fixtures like the Daly Mansion for any evidence of haunting.

Mullen usually works with teams of five to get the cleanest audio and video recordings possible. While he says the public event at the Marcus Daly Mansion offers a lot of energy for spirits to draw on, he can't separate the footsteps of stragglers from the knocks he tries to elicit from the paranormal. Instead, Mullen snaps pictures down hallways now and then, hoping to catch shadows or the blotches of red mist he says are ghosts.

Sometimes the effort pays off. Mullen says he recorded voices at the Old Montana Prison in Deer Lodge in April 2009, and checked the names he heard against old prison records. He's convinced he made contact with Paul "Turkey Pete" Eitner, an inmate of 49 years.

But most of the time, Hawk Paranormal's questions go unanswered. It's a point of serious frustration given that the group—like the rest of the paranormal investigation community—works long nights for no pay in the interests of keeping the profession free from exploitation.

"Yeah, it gets really frustrating," says Mullen, a stay-at-home dad who collects military benefits. "Sometimes you yell at the dark, 'cause nothing's happening."

Many would posit that nothing paranormal is ever actually happening. Joe Nickell of the New York-based Committee of Skeptical Inquiry remains one of the country's leading critics of the paranormal, debunking hauntings and openly railing on shows like "Ghost Hunters."

"Not one ghost has ever been authenticated by science, not one," Nickell told the Albany Times Union in 2008. "They're trying to use the respect of science—hey, look at this fancy equipment—to justify their superstitious beliefs."

Elisabeth Beckett, 18, says she was a skeptic—before she attended the Daly Mansion event. She tagged along with her younger sister Emily, a rabid "Ghost Hunter" fan, but "wasn't expecting anything to happen." Then she says she was touched by something.

"I asked if there was anyone other than Mrs. Daly in the room, and I started to feel really cold," Beckett says. "Then I felt a hand on my back. It wasn't mean or anything. More comforting."

Mullen tries to maintain his composure while listening to Beckett's story, but he's clearly excited. Beckett may not be an instant convert, but she might accept the possibilities of paranormal activity more easily now. And for a ghost hunter intent on proving that his work isn't just a joke, that's promising.

"I'm aware that there are people out there who, if a ghost walked straight up to them and shook their hand, they still wouldn't believe," Mullen says. "However, I know strong evidence might show others that there's something else there."