NEW YORK — Modern theater often involves some degree of interaction between actors and the audience. But paying money to be chased by a blood-soaked lunatic?

New York's Halloween season this year features "Killers: A Nightmare Haunted House" in which the public wanders from room to room, perusing gory sights.

Set up in a theater in Manhattan's Lower East Side, "Killers" is less a traditional haunted house than a walk down the grimmest byways of American criminal history.

Actors lurking in dark corners of the installation play a Who's Who of mass murderers. "Milwaukee Cannibal" Jeffrey Dahmer's there. Ed Gein, who robbed graves and made himself a "woman suit," inspiring the movies "Psycho" and "The Texas Chainsaw Massacre," inhabits another room. Nearby, there's psychopathic clown John Wayne Gacy.

Though haunted houses have long been a staple of Halloween-crazed America, high-budget productions like "Killers" each year push the gore and fright factor to new limits.

For throngs of scare-seekers, each paying between $20 and $60 (15 and 45 euros), the fun starts in the lobby with a display of real-life serial killer artifacts. These include primitive paintings and poems by the likes of Charles Manson, police documents, and the autopsy photos of Dahmer after he was killed in prison.

"It's on loan from someone who wants to remain anonymous, for obvious reasons," the show's spokesman Daniel DeMello said.

Ushers dressed as FBI agents order the crowd into line, before letting small groups enter through the black curtains of the horror house. Those who want to be touched by the actors have fake blood daubed on their foreheads.

Once inside, the loudest sound one hears is screaming - the noise could be from an actor, like the woman watching her leg being amputated by a psychotic doctor, or it could, just as easily, be one of the paying guests.

Chainsaws, a bloodstained corridor, Ted Bundy getting the electric chair, a 16th century Hungarian countess preparing a bath of young girls' blood - even for those not particularly frightened, the staged scenes of depravity deliver a cumulatively creepy effect.

The show's director, John Harlacher, said serial killers have a peculiar resonance in the United States.

"They're all over the world, but in America the culture elevates them to celebrity," he said, adding that in a twisted way, American psychos could even be said to embody the traditional national values of "planning ahead, working hard."

But "Killers" has taken flak for glamorizing and making money out of real world evil.

"I don't know why someone would do something like that," Dorothy Straughter, whose 19-year-old son was among those raped, chopped up or eaten by Dahmer between 1978 and 1991, told the Daily News.

Harlacher, however, said the expected 35,000 visitors to the show won't see any glamour.

"We wanted to strip away the facade. I hope they'll come out of here scared to death," he said. "I hope they'll feel grossed out by the killers."

So what's it like embodying a psychopath night after night?

"A little weird," said actor Scott Kozel, a hefty 25-year-old. He plays Gacy, who did "Pogo the Clown" shows at children's parties and parades in Illinois, ran a successful business, and meanwhile raped and murdered at least 33 young men in the 1970s.

Kozel said his act, in which he pretends to charm male visitors before inviting them to descend through a trapdoor, provokes some extreme reactions.

"We've seen people just lose it. Last week I saw a guy bigger than me, broad, biceps as big as my head, just screaming like a baby."

"If I can get someone running out screaming, that makes my day," said the actress playing Lizzie Borden, who was acquitted in the 1892 ax murders of her father and stepmother in Massachusetts, but remains a sinister folk character to this day.

Among the public this week was a man who knows a thing or two about scaring people: "Exorcist" director William Friedkin. He emerged giving a thumbs up before disappearing with friends into the Blood Thirst lobby bar.

Another visitor, Alexandra Balabuer, 21, was equally enthusiastic.

"It was fun," she said. "I had a lot of fun - I was scared."