A county judge in Kansas, US, has dismissed a number of criminal charges, including murder, against the designers and operators of Verrückt – a record-breaking 17-storey waterslide that killed 10-year-old Caleb Schwab in 2016.

Caleb – son of state representative Scott Schwab and his wife Michele – died riding Verrückt in 2016 on a ride investigators had called “rushed” and “structurally complicated”, adding that it ignored safety issues and replaced mathematical calculations with “crude trial-and-error methods.”

The ride's main designers – Schlitterbahn co-owner Jeff Henry and ride designer John Schooley – had been facing charges for a number of felonies, including involuntary manslaughter, several counts of aggravated battery, aggravated endangering a child and interference with law enforcement. The park's director of operations, Tyler Miles had also been indicted on charges including involuntary manslaughter.

But all charges were dropped by Judge Robert Burns, who said on Friday (22 February) that Kansas attorney general Derek Schmidt had tainted the indictments by calling a witness with "questionable testimony" and showing jurors footage from a Travel Channel TV show that "hyped the ride's dangers". The judge said the footage wasn't intended to show the actual risks of the ride and that the footage could have prejudiced the grand jury.

"We're obviously disappointed and respectfully disagree with the court’s decision," said a statement from the attorney general. "We will review the ruling carefully, including the court’s observation that the ruling ‘does not preclude the possibility that the State could continue to pursue this matter in a criminal court,’ and take a fresh look at the evidence and applicable law in this tragic and troubling case to determine the best course forward."

The Schwab family has already reached a settlement worth nearly US$20m (€17.6m, £15.2m) with the waterpark that ended a civil lawsuit.