The Nightmare Above the Water Park: Inside the Secret “Undertoe” Trafficking Operation

WISCONSIN DELLS, WI — For nearly two years, the Aqua Kingdom Resort stood as a shining example of American family vacation culture. Situated on the bustling Highway 12 corridor of Wisconsin Dells—the self-proclaimed “Water Park Capital of the World”—the $140 million facility was a magnet for millions, a place where church youth groups held annual retreats and elementary schools sent students for fall field trips.

With four-star ratings, 12 water slides, and a wave pool the size of a football field, the resort was a picture of wholesome, corporate-managed fun. But beneath the veneer of sunscreen, chlorine, and shouting children lay a hidden chamber that defied logic, architectural reality, and human decency.

On the morning of November 14, 2025, that illusion shattered.

In a meticulously coordinated pre-dawn raid, 47 FBI tactical agents and 19 Wisconsin State Police officers breached the resort. They were not there for code violations or administrative lapses. They were there to dismantle “Undertoe,” a clandestine human trafficking operation that had been functioning, quite literally, above the heads of unsuspecting families for 26 months.

A Ghost Floor in the House of Fun

The investigation did not begin with a high-tech federal breakthrough, but with a 19-year-old lifeguard who noticed something small, specific, and impossible.

On October 11, 2025, Caitlyn Marsh was working her standard rotation at the wave pool. Like many seasonal employees, she had learned the resort’s rhythms with professional precision. She knew the guest flow, the maintenance schedules, and—crucially—the color-coding system of the guest wristbands.

When three children, aged 8 to 11, entered through a service door wearing retired “yellow” wristbands, Marsh didn’t panic. She acted. When she discovered that the wristbands were not merely outdated, but completely unregistered in the resort’s system, her suspicion deepened. Most importantly, when she walked the children to the pool deck and returned moments later to find them vanished, she knew she had witnessed something wrong.

Her instinct to reach out to an off-duty Wisconsin State Police sergeant, Wade Tilman—who happened to be at the resort for his daughter’s birthday—set the wheels of justice in motion. Tilman’s quiet, unofficial review of security footage confirmed what logic suggested: the children had appeared from a level that, according to every public evacuation map and architectural floor plan, did not exist.

The Architecture of Deception

The “Undertoe” operation relied on a level of structural deceit that investigators are still struggling to fully comprehend. The trafficking cells were located in a mezzanine corridor above the Kids Adventure Lagoon—a space concealed by a laundry tunnel access point and sealed from the outside.

For over two years, the facility passed every state inspection. Fire marshals walked the building. Health inspectors checked the pools. None noticed the mezzanine. The resort owner, Garrett Aldrren, a Chicago-based developer, operated behind a labyrinthine structure of shell companies registered in Delaware and Wyoming.

The financial architecture was equally designed to be mind-numbingly “boring.” Payments flowed from the resort’s operating accounts to a fake nonprofit in Cedar Rapids, Iowa, disguised as “program coordination fees” for transitional foster care. It was a strategy of camouflage through administrative tedium—designed to look like legitimate government contracts to any auditor not specifically looking for evidence of a crime.

The 48-Hour Countdown

When the case reached Special Agent Dana Kowalsski of the FBI’s Milwaukee field office, the challenge became a high-stakes calculation of risk versus rescue.

By early November 2025, the task force had confirmed the existence of the mezzanine and the trafficking network’s connections to properties in Rockford, Illinois, and Rochester, Minnesota. The dilemma was agonizing: move now and rescue the children, or wait and attempt to take down the entire multi-state network simultaneously?

“The discussion ran three hours,” a source familiar with the task force’s deliberations noted. “The debate was about whether to attempt coordination… or to move on Wisconsin and trust that the speed of the Aqua Kingdom arrest phase would outpace the network’s ability to respond.”

Kowalsski made the call to move on November 14th. However, the network itself forced their hand. Two days prior to the raid, surveillance teams spotted a black cargo van—an anomaly in their established patterns—approaching the resort’s service dock. The transport window was closing. The traffickers were preparing to move their “inventory.”

The Breach: 3:14 A.M.

The raid was a masterclass in tactical synchronization. At 3:14 a.m., as the resort slept, Team Charlie utilized a custom-built bypass device to breach the proprietary keycard locks of the laundry tunnel.

They found a long, disorienting concrete passage approximately 90 feet long, containing three rooms secured by simple storage padlocks. Inside, they found 15 individuals: 14 children and one woman, approximately 30 years old.

The woman, investigators later confirmed, was not a perpetrator but a victim coerced into serving as a caretaker under direct threats to her own family. She was released without charges, a survivor herself in a web of exploitation. The 15 children, aged 7 to 14, were found alive. While some showed signs of malnutrition and trauma, all were ambulatory and immediately provided with intensive on-site care before being moved to a secure DHS facility.

The Failure of Institutional Trust

The fallout from the Aqua Kingdom raid has sent shockwaves through the hospitality and child-welfare sectors. The arrests that followed were swift: the resort’s night security manager, maintenance crew members, and the owner’s brother-in-law, Craig Hartwell, were taken into custody. Aldrren, the managing partner, was arrested at his Chicago home.

But for many, the horror lies in the “calculated exploitation of institutional trust.” Aldrren and Hartwell did not just run a trafficking operation; they ran one inside a sanctuary of family life. By leaning into the trust families place in church retreats and school trips, they weaponized the very institutions designed to protect children.

“They operated a trafficking front inside the exact kind of institution that families have been conditioned to trust completely,” an investigator noted. “That is a different category of deliberateness.”

The Long Road to Identity

Perhaps the most chilling aspect of the discovery is that none of the 15 children were in the National Center for Missing and Exploited Children database. They had been erased.

The forged foster documentation had assigned each child a fabricated identity—a fake name, a fake case number, and a fake Iowa DHS file reference. They weren’t just missing; they were ghost-people, intentionally hidden in a paper trail that made them appear as though they were already being “helped” by the state.

As federal prosecutors move toward trial, the case against Aldrren and his associates is expected to center on these aggravating factors. For the families who once considered Aqua Kingdom a vacation destination, the realization is profound: the danger was not just in the water, but in the walls.

For now, the focus remains on the long process of trauma recovery for the survivors. The “Undertoe” operation has been dismantled, but the questions it leaves behind will haunt the industry for years to come. In a world where families trust large, branded institutions to keep their children safe, the story of the Aqua Kingdom Resort serves as a brutal reminder: even in the places where “family fun never sleeps,” the shadows can hide in plain sight.

Frequently Asked Questions

What was the “Undertoe” operation? “Undertoe” was a human trafficking network operating out of a hidden mezzanine level at the Aqua Kingdom Resort in Wisconsin Dells, as well as properties in Illinois and Minnesota.

How were the victims hidden? The traffickers constructed a concealed corridor above the resort’s Kids Adventure Lagoon, accessible only through a restricted laundry tunnel. They used forged foster care paperwork to assign children fake identities, effectively erasing them from national missing persons databases.

How was the operation exposed? A 19-year-old lifeguard named Caitlyn Marsh noticed children wearing retired wristband colors. Her report to an off-duty state trooper led to a discovery of the hidden floor plan and subsequent FBI surveillance.

What is the status of the accused? Several individuals, including resort managing partner Garrett Aldrren and Craig Hartwell, were arrested following the November 14th raid and face federal charges related to trafficking and racketeering.

Were the children recovered safe? Yes, all 15 children found in the mezzanine were alive. They received on-site medical and nutritional assessment before being placed in the care of the Department of Homeland Security’s child welfare coordinators.