It was a swanky, late-night sex club where married couples gathered to swap spouses or arrange orgies.

Despite complaints about fights, noise and the illegal sale of alcohol, the Detroit Police Department was rarely a problem, even though its Central District headquarters was a few blocks away.

Turns out, on-duty Detroit cops were providing security and limos for the upscale, tight-knit clientele who gathered at the Forest Club at 300 E. Milwaukee, according to complaints under investigation by city and federal authorities, the Motor City Muckraker has learned from sources at city hall and the police department.

Some off-duty police attended the events with a spouse, according to sources, who spoke on condition of anonymity because the probe is ongoing.

If true, it would mark yet another shameful scandal embroiling a police department that is shedding jobs and losing its focus on fighting escalating crime. The department is without a permanent police chief, and morale has plummeted following 10% pay cuts and reductions in health care.

“This looked suspicious from the beginning,” a city hall source said. “How do you operate an advertised club so close to a precinct and not take notice? Come on now.”

The club, which was accused of selling alcohol without a liquor license, no longer exists, but the operator, Fullmoon Seductions, still has sex parties at local hotels, according to its website.

“We are Fullmoon Seductions, a private social club for swingers of all races that love urban swinging,” the site reads. “A few years ago, we decided to ditch the big club swinger club we ran and concentrate on throwing a more intimate, sensual hotel party on a monthly basis. The focus of our Intimate Rendezvous events is Sensuality, Intimacy, Discretion and Eroticism.”

The Forest Club, which couldn’t be reached for comment, wasn’t the only sex operation a few blocks from police headquarters.

In September, Sheriff’s deputies – not Detroit police – raided a nondescript club at 29 E. Baltimore near Woodward and Grand Boulevard and confiscated guns, drugs, $10,0000 in cash and about 50 cars in what was described as an after-hours club with rooms for prostitutes.

A 16-year-old girl was found in the building.

More than 130 people were ticketed; the club’s 10 operators were arrested.