A woman was taken to hospital with serious injuries after falling from a fair ride in East Yorkshire.
Police believe she fell from one attraction to another at Hull's base on Monday night, with a teenager also injured after being hit by women when she fell.
Both tours ended while investigating Hull City Council health and safety officials and officials, while the woman continues to receive treatment after being taken to hospital.
It is believed that her injuries are not life threatening or life-changing, and the teenager was not seriously injured.
The accident occurred just days after the opening of the popular and long-term fair, held over a week in October of each year.
It opened on Friday and runs until next Saturday.
Chief Inspector Paul Kirby, Hull Fair's tactical commander in Humberside Police, called for help in efforts to establish what happened.
"We have very well-established plans in place with the board for any such incident at the fair, and I want to thank everyone for their patience as we deal with it," he said.
"I ask anyone who may have seen what happened or who has a video of it to contact us."
:: Anyone who has information that can help with the investigation should call 101, quoting log 514 of 10/10/19.