CHICAGO (STMW) — The sign on the locked door said “Christian Consulting — by appointment only.”

Any passer by who looked through the window on the 5300 block of West Devon would only have seen a portrait of Christ, hanging in the foyer, and a church pew.

But there was no phone number listed for the new storefront business that sprung up on the Northwest Side in Sept. 2012.

And hidden behind the painting of Jesus, unseen from the street, lay a secret world of unimaginable horrors — a purpose-built torture chamber, complete with a reinforced butcher’s counter for hacking up corpses; a man-sized sink for draining blood; a shower, for the killers to rinse off in; even a small table for them to put their coffee on while they tortured their victims.

Steve Mandell, the 62-year-old alleged would-be killer who prosecutors say built it, had a cheerful name for his creation: “Club Med.”

Its construction and the planning behind it took center stage in federal court on Wednesday, the second day of what’s expected to be Mandell’s two-week trial for a pair of separate murder plots.

Taking the stand again Wednesday, the government’s star witness, shady former North Shore banker George Michael, introduced and explained secretly-recorded tapes he made of Mandell discussing the design for the torture chamber.

“This place would’ve made Stalin proud!” Michael told Mandell in one conversation.

Mandell hoped to make at least $100,000 by kidnapping Riverside businessman Steve Campbell and taking him to “Club Med,” where Mandell and his accomplice Gary Engel would first tie up Campbell and extort him into turning over his wealth, then kill him, the feds allege.

And Mandell had precise requirements for his workplace, according to the tapes.

In one taped conversation, he instructed an unwitting carpenter to make sure the chopping counter could handle 200 to 300 pounds.

The sink should be a “Two compartment [model]… two feet” deep, he said, and the garage door mechanism should be quiet so nobody could hear them coming.

But he didn’t want to spend too much. “I want junk,” he told another construction worker, telling Michael, “This is not the Good Housekeeping Award.”

Michael, who also showed jurors photos of the clean, almost clinical, finished torture chamber, testified that he tried to please Mandell by promising he’d steal heating from a neighboring unit.

And Michael laughed along as Mandell predicted Campbell would defecate on himself during torture and mocked the crying sounds Campbell would make as his genitals were mutilated, another tape showed.

“I’m in a car alone with him and I’m scared — I’m acting,” Michael testified Wednesday.

Mandell also allegedly plotted to kill Anthony Quaranta, the co-owner of Polekatz strip club in Bridgeview, in a bid to seize control of the club’s profits, the feds say.

In one tape played for jurors, Mandell told Michael he’d kill Quaranta and his wife at their home while their kids were at school, then call the wife of the club’s other owner, Demitri Stavropoulos, and warn her, “I’ll show you what Elmwood Park really looks like.”

Asked what Mandell meant by the reference to the suburb where a number of noted mobsters live, Michael testified, “I’ll show you how to kill.”

Michael, who says he was introduced to Mandell by alleged Outfit associate and former cop Fred Pascente, testified that Polekatz’s owners are also Outfit-connected, but that “Mandell wasn’t scared of anybody.”

And on yet another tape, Mandell boasted he was “an old ex-cop — I know how to do surveillance,” even suggesting he was sexually aroused by the plot.

He denies all charges and will take the stand later in the trial to argue he was simply trying to con Michael, and that he would never have followed through on the murder plots, his attorney told jurors Tuesday.

But Wednesday’s testimony seemed hugely damaging to his defense. It included lengthy tapes in which Mandell coached Michael how to prepare an alibi, “lawyer up” and lie to police.

Michael assured Mandell that he knew how to avoid attracting police attention. Making a reference to a scene in the movie “Goodfellas,” Michael said that after he got his cut of the loot, he wouldn’t go out “with a fur coat and a pink Cadillac.”

Mandell, who owns a home in Naples, Fla., replied that after he’d pulled off the murders, “I just want to be the guy in Naples running down the beach with a smile on his face, and nobody knows why he’s smiling.”

Instead, he was arrested behind Michael’s office on Oct. 25, 2012, just moments before he planned to set his grisly scheme in motion, the feds say.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2014. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)