Harrowing footage shows rescue effort of man just before he suffered 'worst death imaginable'

Footage filmed above a cave system in Utah shows the unsuccessful rescue efforts that went into trying to save a father who got stuck upside down in one of its passages.

Thinking he'd found the passage, John crawled inside head first. By the time he realised it was the wrong passage, John was already stuck.

His brother, Josh, was the first to find him and attempt to pull him out, but he had no luck. He went to get help, and rescuers began an hours-long operation in an attempt to free John from the tight passage.

Reporter Fields Moseley was among those on the scene, and described how rescuers had managed to pull John into a more comfortable position, but there was still 16 feet of passage separating him from 'freedom'.

The initial efforts to move John turned disastrous when one of the pulleys failed and he slid back further into the hole.

"It's still far from being a recovery; it's a rescue," Sergeant Tom Hodgson, from the Utah County Sheriff's Office, said. "But the longer it goes, obviously, the more concern there is."

Moseley pointed out that things only became harder as John became more and more tired in the passage, as he would be less able to help rescuers with their mission.

"They need him to put some effort into it and maybe get himself out, but he is exhausted," Moseley said. "They're very worried about him."

The space around John measured just 10 inches by 18 inches, meaning he had no room to turn around, and couldn't wiggle out backwards.

Rescuers were unable to get to John's body even after he died, so a week after he passed away officials sealed off the cave with his body still inside.

The cave remains closed out of fear that other people may become trapped in the passages.