It's not unusual for Slippery Rock University theater professor David Skeele to hear footsteps behind him as he stands on stage in the school's Miller Auditorium, only to turn around to see that nobody's there.

Those and other incidents have convinced scores of Slippery Rock students and professors that someone is haunting the theater, most likely university trustee Emma Guffey Miller, who died in 1970.

Last night, a team of paranormal investigators staked out the theater to find out.

A 10-person crew from Titusville-based Baelfire Paranormal Investigation wired the theater with infrared cameras, voice-recording equipment and electromagnetic sensors, hoping to make contact with Ms. Miller or capture some evidence of an otherworldly presence.

They planned to stay all night looking for orbs, mists or apparitions, said Baelfire owner John Lewis.

"Basically, our biggest goal is to make contact," he said. "We want to know why they are here, why they haven't moved on, do they want to stay?"

In her day, Ms. Miller was a prominent political figure and friend of Eleanor Roosevelt. She donated money for the theater, and the auditorium was later named for her.

Tales of ghost-induced oddities abound there, from costumes disappearing and reappearing just before a show, to mysteriously falling objects, to seeing a moving figure that suddenly vanishes.

Particularly strange things happen in "Emma's Closet," a cramped back room in the theater that holds clothes that Ms. Miller donated before her death.

Dr. Skeele said that he was once watching television in his office and turned the volume down, only to turn his back and hear the volume get turned back up.

"Nobody likes to be here alone late at night," he said. "They try to get from one place to another as quickly as possible."

Mr. Lewis said it would take about two weeks to make a determination as to whether the theater is officially haunted. On average, he finds evidence of paranormal activity in about 40 percent of his investigations, he said.

About a month ago, Mr. Lewis read accounts of the possible haunting in Slippery Rock and contacted the university to see whether he could officially investigate. The school is not paying Mr. Lewis for his services, said Slippery Rock spokesman Gordon Ovenshine.

As investigators started to set up their equipment last night, they did receive some unexpected guests. A few members of the community -- some fans of television shows such as Ghost Hunters and TAPS -- heard about the investigation and turned up to watch.

As for Dr. Skeele, he's hoping the investigators turn up some concrete proof that the theater is haunted. But he doesn't necessarily mean that he wants Ms. Miller to leave.

"If anything, we're getting inspired," said Dr. Skeele. "We do edgy, difficult theater. Sometimes I feel like we're getting assistance."