(NECN/NBC News: Chris Clackum) - Thursday night at the North Carolina State Fair in Raleigh, just as riders were getting off the ride called the Vortex, it suddenly jolted back to a start.
Five people were hurt, and two seriously, while others were frightened by what they saw.
"It just sounded like a bunch of stuff hitting metal," said one witness.
The Vortex, a pendulum swing ride, is a new ride at this year's North Carolina State Fair.
And like all rides at the fair, is supposed to be inspected three times a day.
Still investigators can't say what went wrong Thursday night; whether it was mechanical or human error.
"It would be great if we could stand up here this morning and tell you exactly what happened. Unfortunately, we're not at that point yet," said fair spokesman Brian Long.
The fair itself reopened as scheduled Friday morning.