Jeff Henry and his longtime friend and business partner, John Schooley, had coupled an ambitious goal with an impossible timeline: Build the world’s tallest waterslide and get it featured on a Travel Channel show about water parks, all in a few short months.

What the two men did not have, prosecutors say, were credentials in mathematics, physics or engineering — essentials to safely bring their dream to fruition.

It ended tragically in August 2016. Ten-year-old Caleb Schwab was decapitated on the ride named Verrückt — the German word for “insane.” The ensuing swarm of investigators said they found signs of rushed construction and a trail of negligence leading back to Henry and Schooley, prosecutors say.

Now, the two men — magnates of the American water park industry — face second-degree murder charges. The 168-foot-7-inch tall ride — taller than Niagara Falls — has been closed, and the Guinness Book of World Records page that featured Verrückt as the world’s tallest waterslide now gives viewers an error message.

Henry was arrested March 26. Schooley, who was out of the country when the grand jury indictment was unsealed, was arrested by U.S. Marshals when he landed at Dallas/Fort Worth airport Monday night, according to Dallas NBC-affiliate KXAS.

Henry, who owned the Schlitterbahn water park and several others with his siblings, was called a visionary before he opened the world’s tallest waterslide.

Ride designer Jeff Henry looks over his Verrückt creation in July 2014. The ride, at Schlitterbahn Waterpark in Kansas City, Kan., was billed as the world’s tallest waterslide. (Charlie Riedel/AP)

A hybrid roller-coaster and waterslide ride, Verrückt was his brainchild. Investigators say he decided to build it in a “spur-of-the-moment bid to impress producers of Travel Channel’s Xtreme Waterparks series.” Schooley helped with the design — and later the testing.

On Verrückt, groups of riders first zoomed down a nearly vertical, 168-foot main descent. Then they ascended 50 feet above the ground, propelled by inertia and “a series of high-pressure water blasters,” according to the indictment. But in some instances, instead of sliding straight down, the rafts went airborne — a major design flaw that investigators say the company had known about, tried unsuccessfully to fix and eventually ignored.

Most of the slide is covered with a net suspended by metal hoops, an industry-defying addition that investigators say hints at Verrückt’s danger.

The indictment says the ride creators’ calculations were off and that they knew it. Some of the rafts would go airborne before the second drop, causing riders to strike the net or the suspended metal hoops that held it.

And month after month, injuries piled up.

In the two years that Verrückt was in operation, 13 people were injured, many after the rafts left the slide, according to court documents.

A month after the ride opened, a 14-year-old received a concussion, court papers say. The next summer, another teen was concussed, and a 20-year-old woman suffered a slipped spinal disk. The woman, Brittany Hawkins, was a lifeguard who knew the park’s operator and told him she was injured after her raft went airborne.

The indictment accuses the former director of operations, Tyler Austin Miles, of intercepting incident reports from lifeguards and destroying witness statements — then coaching the guards to write statements, which omitted crucial damaging details about Verrückt. He has been charged with involuntary manslaughter and several counts of aggravated endangerment and aggravated battery.

Even before Caleb died, the ride terrified park employees who had to operate and test it, a former lifeguard at the park told Kansas City Fox-affiliate WDAF.

“We had to ride it three times before we actually opened the park every day,” Nathan Campbell said. “They would ask lifeguards who would want to volunteer, and no one would put their hands up.

“ … It was like, ‘no, I don’t want to do it.’ They are just making us, like, ‘oh, yeah, go test this, it is fine,’ even though the test dummies fly off.”

One day, Campbell was chosen to be the morning tester. On the third trip down, the raft flipped and crashed into a wall. He went home with a back injury, and a report was never written, he told the news station. That was the last summer he worked at Schlitterbahn.

Caleb climbed into the front seat of one of the ride’s rafts Aug. 7, 2016, which the park had dubbed Elected Official Day.

By the end of the minute-long ride, Caleb, the son of Kansas state Rep. Scott Schwab (R), was dead after being decapitated. Two women riding with him suffered cuts and fractures. Their raft had collided with a metal pole that held the net.

Schlitterbahn spokeswoman Winter Prosapio took issue with several claims in the indictment and denied that the company and Miles withheld or altered evidence.

Caleb’s death, she said in a statement emailed to The Washington Post, was the result of an accident and not of a crime:

We were shocked by the allegations being made by the Attorney General about Tyler and our KC park. The allegation that we operated, and failed to maintain, a ride that could foreseeably cause such a tragic accident is beyond the pale of speculation. Many of us, and our children and grandchildren, have ridden the ride with complete confidence as to its safety. Our operational mantra has been and will forever be Safety First.

The accusation that we withheld information or altered evidence is completely false. We have operated with integrity from day one at the water park — as we do throughout our water parks and resorts. We put our guests and employees safety first; and safety and maintenance are at the top of our list of priorities.

A simple waterslide can require months of calculation, computer modeling and prototyping by trained engineers before builders break ground. But investigators say that engineers were never directly involved in Verrückt’s conception or design and that Henry, Schooley and their team completed a prototype within 36 days.

Because of the rush, the indictment says, they “skipped fundamental steps in the design process. In place of mathematical and physics calculations, they rushed forward relying almost entirely on crude trial-and-error methods.”

Emails from Henry spoke of the pace to get the ride up and running.

“I must communicate reality to all. Time, is of the essence. No time to die. J.” he said in one email. In another: “This is a designed product for TV, absolutely cannot be anything else. Speed is 100% required. A floor a day. Tough schedule.”

In some instances, they watched dummies speed down the hill and then fly off the ride, the court documents say. Still, the ride sped toward its opening.

“Verrückt could hurt me, it could kill me, it is a seriously dangerous piece of equipment today because there are things that we don’t know about it,” Henry wrote in one message. “Every day we learn more … I’ve seen what this one had done to the crash dummies and to the boats we sent down it. Ever since the prototype. And we had boats flying in the prototype too. It’s complex, it’s fast, it’s mean. If we mess up, it could be the end. I could die going down this ride.”

Verrückt waterslide designers, John Schooley, left, and Texas-based Schlitterbahn Waterparks and Resorts co-owner Jeffrey Henry, speak in 2014 about the challenges of opening the 17-story tall attraction before its operation in Kansas City, Kan. (Monty Davis/Kansas City Star/AP)

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