As paranormal investigator John Lewis stood behind the stage in Slippery Rock University's Miller Auditorium three weeks ago, he felt someone hit the back of his knee.

He and three people there with him heard a little girl's laughter, then footsteps, as if someone was running away. But there was no little girl.

Mwaaahahahaha! (That's a fright-filled, maniacal laugh.)

It's official, folks. Miller Auditorium is haunted. But the good news is, they're friendly ghosts.

"Almost everyone on our team had personal experience," Mr. Lewis, owner of Titusville-based Baelfire Paranormal Investigation, said yesterday at a news conference in the theater lobby. "I pretty much feel this place is haunted."

On Feb. 28, he and his 11-member crew spent the night in the auditorium looking for evidence of paranormal activity. Free of charge, they set up infrared video cameras and had digital and 35mm still cameras and digital, analog and micro-cassette audio recorders.

Eleven hours of audio and video and 758 photographs later, they believe to be true what professors and students have suspected for years.

In addition to personal experiences, investigators captured inexplicable digital images of a thick, neon green mist in that same backstage area -- the scene shop -- and heard voices.

"I wish I could say we caught an apparition," said Mr. Lewis, who hasn't yet analyzed the video recorded that night. But they can't.

Just four distinct voices -- two males, a little girl and an older woman.

"We heard what we feel is an adult female voice saying, 'Enough!'" he said, playing the audio file of a woman's voice clearly saying the word. "We do believe that could be Emma Guffey Miller."

Many believe Ms. Miller, a university trustee who died in 1970, has haunted the auditorium named after her for years. Investigators plan to forward the voice audio file to Ms. Miller's granddaughter for possible identification.

"If she can recognize the voice, that would give us some hard scientific evidence that it's her," Mr. Lewis said.

They haven't identified the little girl, but think one of the men could be a former student who died tragically.

"We expected to come in here and maybe get lucky and find Emma," Mr. Lewis said. "To come up with four entities, that was a lot, more than we expected."

For years, students and staff have experienced odd goings on in the theater, including vanishing ghostly figures, disappearing and reappearing costumes and falling objects, especially in "Emma's Closet," a cramped back room holding clothes Ms. Miller donated to the school.

"It's fantastic," said Slippery Rock theater professor David Skeele, who in the past has heard footsteps on the stage behind him only to turn around and find no one there. "I didn't expect them to get so much."

He's happy to have confirmation of what students and faculty have been experiencing. Sightings, few and far between in recent years, were almost a nightly occurrence in the early 1990s, he said.

"This is the best possible outcome for us and what everyone wanted to hear," said Dr. Skeele, who is open to the idea of ghosts. "If it wants to be here, I'm happy to let it."

Other phrases investigators recorded included "Get away!", "Let go" and "Stop talking." At one point during the night of the investigation, Mr. Lewis said, "The people here love Emma. They just want to know for a fact that you're here."

To which, he says, someone replied, "Yes."

And when his team packed up its equipment around 4 a.m. on March 1, a voice said, "Goodbye."

Rebecca Morrice, a Slippery Rock assistant theater professor who also handles Ms. Miller's clothing collection, found the report interesting.

"I tend to believe it more than not, but I'm kind of on the fence," she said.

During her 12-year tenure, people have reported seeing an old woman, an older man and a young girl in the auditorium. Most of her experiences have been with Ms. Miller's spirit, which she and other students believe has been a lucky charm, helping them prepare for a production, for example, finding a missing costume in the nick of time.

"Sometimes, things that should have fallen apart just magically come together in the end," she said.

That's Emma.