KANSAS CITY, Mo. — A Kansas waterslide billed as the world’s tallest remained off-limits Monday as authorities pressed to figure out how a state lawmaker’s 10-year-old son died of a neck injury while riding it.

Details remained murky about what happened Sunday to Caleb Thomas Schwab on the 168-foot-tall “Verruckt” – German for “insane” – that since its debut two years ago has been the top draw at Schlitterbahn Waterpark in Kansas City, Kansas.

Kansas City police said in a written statement Monday that Caleb suffered a fatal neck injury around 2:30 p.m. while he was riding the slide with two women, neither of whom was related to him. They suffered minor facial injuries and were treated at a local hospital, police said.

Emergency responders arrived to find the boy dead in a pool at the end of the ride, according to the statement, which offered no further details.

In a statement Monday afternoon, Schlitterbahn said it was “deeply and intensely saddened for the Schwab family and all who were impacted by the tragic accident.” The park was tentatively scheduled to reopen Wednesday, but “Verruckt is closed,” according to the statement.

Officer Cameron Morgan, a police spokesman, said no police report about the incident was available. He said investigators were treating Caleb’s death as a “civil matter” rather than a criminal one and referred additional questions to the park.

Leslie Castaneda, who was at Schlitterbahn on Sunday, told The Kansas City Star that she saw Caleb’s crumpled shorts or bathing suit at the bottom of the ride, along with blood on the slide’s white descending flume.

“I’m really having a tough time with it. I really am,” said Castaneda. “I saw his (Caleb’s) brother. He was screaming.”

On the waterslide certified by Guinness World Records as the world’s tallest, riders sit in multi-person rafts during “the ultimate in water slide thrills,” subjecting “adventure seekers” to a “jaw dropping” 17-story drop, the park’s website says. Passengers then are “blasted back up a second massive hill and then sent down yet another gut-wrenching 50-foot drop.”

In a 2014 news article linked to one of the delays in the opening of Schlitterbahn, co-owner Jeff Henry told USA Today that he and senior designer John Schooley had based their calculations when designing the slide on roller coasters, but that didn’t translate well to a waterslide like Verruckt.

In early tests, rafts carrying sandbags flew off the slide, prompting engineers to tear down half of the ride and reconfigure some angles at a cost of $1 million.