MELROSE PARK, Ill. (CBS) — They are a group of Chicago area police officers by day, and paranormal investigators at night.

When someone claims to have an encounter with the unknown, their job is either to refute or prove it with evidence.

They brought CBS 2’s Susan Carlson to one local haunt where they recently made a scary discovery. The look of it alone is enough to give one the creeps.

Big Timers Sound Shop, at 171 N. 25th Ave. in Melrose Park, is not scary at all from the outside. But when a worker claimed to hear voices and refused to go in the basement, he called the Paranormal Cops.

In an episode on A&E, the real-life ghostbusters believed they had a hostile interaction with … something. It whispered: “Get out. Get out of here.”

With a little digging, they discovered filled-in tunnels, and a hidden stairway behind a mirror in the women’s restroom.

It turns out that in a prior incarnation, Big Timers was a Chicago Outfit haunt called Casa Madrid. The restaurant and gambling den closed in the 1960s, but during its time, beatings and murders reportedly took place, the Chicago Sun-Times reported. It was owned by the late mobster Rocco “Gumballs” DeGrazia, the newspaper reported.

“We brought a former patron down here and he told us about one or two shootings that he was aware of, and we found blood to corroborate what he told us,” said Paranormal Cops founder Ron Fabiani,

CBS 2 walked through Big Timers with a device to pick up electromagnetic energy, often associated with the paranormal.

“It’s so cold, I can see your breath,” Carlson said as she toured Big Timers. “I have goose bumps.”

The sentiment is shared by the Paranormal Cops.

“When I went in there my intuition went to a level 10 right away,” said Paranormal Cop Tom Froelich.

Fabiani and Froelich are both a longtime police officers, but they still gets scared.

“On the inside, I’ve been scared many times,” Fabiani said.

“As cops, we don’t have the luxury of embellishing,” added Froelich. “Our job is to provide credible answers and that’s what we do in this group – provide credible answers for people.”

The paranormal cops respond to about four calls a month of unexplained phenomena in the Chicago area. They say about half the cases turn out to be nothing.

Of the other half, they say many of those cases are what they believe is contact by a deceased loved one or a peaceful spirit, simply watching over us.

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