The owners of a zorb that rolled off a cliff at a Russian ski resort, killing one man, are reportedly on the run.
Russian authorities want to question the three owners of the zorb, which killed 27-year old Denis Burakov and injured his friend Vladimir Shcherbov, to see if they failed to provide a safe service, the BBC reported.
The men who rolled the zorb off on its fatal ride have reportedly fled the scene now a criminal investigation has been opened, it said.
Burakov suffered severe spinal injuries inside the inflated plastic ball and died on the way to hospital.
Shcherbov reportedly remains in a critical condition in hospital after he tried to stop the zorb, which eventually came to rest on a frozen lake.
The New Zealand inventors of the extreme sport said the death could have been prevented had the operator been following its safety code.
"This tragedy was committed by an operator who has no association with Zorb, and was not known to Zorb," Hope Horrocks, chief executive of Zorb Ltd, said.
"Zorb has published a code of safe operations and invites competing operators to sign on to the code and adopt Zorb's world proven safety standards."
The adventure sport has been running since 1994, when it was invented here. Like bungy jumping, zorbing has taken off worldwide but there is no regulatory body.
Horrocks said one of many dangers visible in the now-viral YouTube video of Burakov's death was a double-harness configuration.
"Zorb does not operate, nor manufacture double-harness spheres," she said.
"There are clear and obvious dangers in such a configuration and Zorb prohibits double-harness globe riding on its licensed sites.
"This accident was completely avoidable if those standards had been adopted."
Horrocks said there was also a lack of berms, which was "completely prohibited" for Zorb-licensed operators.
Berms are the ridges which form the track a zorb ball would follow, guiding its path down a slope.
Instead, Burakov's zorb was left to roll freely down the side of the Dombai Resort complex in Russia's North Caucasus mountain range.
The YouTube video of the incident shows Burakov careering out of control, but the cameraman and spectators don't realise until it's too late.
Speaking in Russian, people can be heard saying "Oh f***, it's gone in the wrong direction again."
After it drops out of view, someone asks: "What's going on there?"
"A catastrophe," someone else replies.
Then the footage is stopped.