When Michael Zimmer was 10 years old, his bedroom door opened and he heard footsteps come into the room, but he could see in the moonlight that there was no one there. He opened his mouth to scream, but he was so terrified that no sound came out.

Several years later, he was spending the night at the farm where his grandfather had died a few months before, when he heard someone come down the stairs, sit in the rocking chair, get up and walk past the window -- where he could see that there was no one there.

He then heard the footsteps go out the door. It's a pattern his grandfather had followed each morning when he got up to milk the cows. This time, Zimmer says, he wasn't scared, because he knew what it was.

These early experiences contributed to his lifelong interest in ghosts. In 2000, he became associated with the Ogden-based group Utah Paranormal Exploration & Research (UPER).

A notable investigation with that group was at Dead Haven, an Ogden spook alley where the team gathered evidence about the presence of an elderly woman who had suffered a violent accidental death in an apartment located there in the 1970s.

UPER splintered in 2004, and Zimmer became the director of a team called the Paranormal Investigations Team of Utah, a nonprofit group whose members are now based mostly in Salt Lake.

In 2007, the P.I. Team of Utah became the only group in the state to be affiliated with The Atlantic Paranormal Society (TAPS). The Rhode Island-based group have become so popular from "Ghost Hunters," the SyFy channel reality series about their activities that launched in 2004, that they've had to form a network with other groups around the country in order to handle the demand for their services.

Zimmer says he's quite honored that his group passed the extensive written and phone interview process to become part of the TAPS family. The PI Team of Utah conducts 30 to 40 investigations per year, Zimmer says.

On Oct. 16, they were invited to investigate the Midvale Main Street Theatre (7711 S. Main St.), where rehearsals for a November production of "Steel Magnolias" have been under way. The staff has experienced some unusual events, including lights coming on by themselves, and a rocking chair onstage that started rocking on its own and then stopped abruptly.

Zimmer arrives at the theater shortly before 10 p.m., with two of his four active teammates: Amber Hamaker and Heather Ranck. The team sets up a video camera aimed at the stage, and places an audio recorder under the rocking chair. Hamaker carries a parabolic microphone to amplify sound, and the team carries other tools like digital cameras and an electromagnetic field reader.

After their equipment is in place, they spend some time sitting in the darkness of the theater, attempting to record some Electronic Voice Phenomena (EVP), the name ghost hunters have given to the occasional tendency for voices they didn't hear at the time to show up on their audio recordings.

At first the team tries asking questions aloud, such as "Why are you here?" and "Do you like to watch the shows?" After a while, Zimmer explains that they often have better luck recording EVP if they just chat with each other, so I take the opportunity to ask them about their histories.

Hamaker, who worked as a radio signal interceptor for the military, joined the team about four months ago as a specialist in EVP analysis. When she was 6, she tells me, she visited the Shiloh Civil War battlefield, where she saw soldiers that no one else saw.

When she was older, she was sleeping on an air mattress on the floor at a friend's house when she opened her eyes and saw the form or a man standing in the hallway about 15 feet away. She blinked, and he was 5 feet away, then 15 feet away again.

Upon questioning her friend the next morning, she learned that there was indeed "something weird" in the house that he liked to play tricks on the occupants ... which could explain why she found her soap in the freezer.

Ranck joined the team this past July. Her assets include her ability to get along with people and having the time and interest to analyze a lot of data.

When she was in middle school, she woke up out of a dead sleep and saw mist cross her bedroom toward a window. Later, after they'd moved, her parents told her that a man had murdered his wife in that house, and she'd been known to stare out the windows, usually wearing a gray gown.

So what drives this team to do this research, I wonder? One goal, says Zimmer, is to help people who are troubled by unexplained events.

Many of their investigations are in private homes, and they often find that seemingly paranormal phenomena are the result of high electromagnetic fields due to faulty wiring in older homes. High EMF fields, says Zimmer, can cause hallucinations and create the feeling of being watched.

If the team can't help explain away a phenomenon, they can help people become less afraid of them by bringing more understanding. "We've had people accept it," he says. "As long as it stays in this part of the house, or it doesn't bother them in bed at night."

When I ask what kinds of words he's recorded in EVPs, he says that a very common one is "Need help."

"Neep help with what?" I ask.

"That's a good question," he replies, explaining that that's the other main goal of the group, to "get just one piece of evidence that would add to the overall answer."

"The answer?" I ask, in the darkness.

"Just to whatever is out there, what is causing this," he says, from his seat on the stage. "Like, is EVP hearing voices of the dead? Is it a parallel universe? Is it something that can be explained? Why have we feared ghosts for centuries? I'd just kind of like to know what's on the other side, what happens after we die."

As we sit, we hear a few clicks and clanks from around the room, but there's no way to know whether it's just the air conditioning system settling down. After a time, we move on to sit in one of the dressing rooms.

Zimmer tells me the group gets two or three membership applications a week, but most don't merit much interaction. He says he needs dedicated, level-headed people who will follow up.

"Some people have watched every episode of 'Ghost Hunters' and are just looking for the thrill but don't have the patience to put in the work," he says.

"They see the best investigations, where they got things. They don't show the ones where you sit there for hours and there's nothing," Hamaker adds.

Usually, Zimmer says, the team doesn't find something the first time they visit a location, especially if there's a large group. He hopes they will be able to make a return to the Midvale Main Street Theatre in November to try to catch the ghostly rocking chair occupant in action.

For more information about The Paranormal Investigations Team of Utah, visit www.piteamofutah.com