Nick Mendenhall said he witnessed the fatal moments in disbelief, watching the man come out of his seat and then fall into another cart on the ride before falling to the ground.

“It was just super, super bizarre, traumatic. I mean, it took me a couple of seconds, I feel like, to process what was going on,” he told the AP. “I cant believe that I just saw that.”

He said his mind instantly went to the trauma of all of those impacted by what he witnessed, including the man’s loved ones and everyone who was on the ride with him.

One witness told NBC affiliate WXIA that the incident was captured in souvenir photos that were automatically taken of the rollercoaster while it was in motion. The BBC has not been able to verify this statement.

Connor Thompson told the BBC’s US partner CBS News that he was in line for the ride when everyone started “yelling, clearly distressed”.

“Everyone was kind of confused at first, and then there was someone who was yelling, ‘Call 911! Someone fell out!” he said. “At first it was almost like I didn’t believe it because I thought that was like impossible for something like that to happen.”

He said he saw the cart come into the hub where others were waiting in line and could see the restraint was unlatched.

Another witness, CiCi Nelson, told CNN she, too, was in line to ride the Goliath when the rollercoaster returned and she saw an empty seat with a loose safety bar and a female covered in blood.

Nelson described a scene of hysteria, adding that one man was “freaking out, saying someone fell off”.

Brittany Landry, who believed she saw Kariem ejected from the rollercoaster, told Fox News she was in tears.

“I broke because we were just on there,” she said.