An accident at a theme park in Altoona, Iowa has left one person dead and three injured.

A post on Adventureland Park’s Facebook page revealed that the incident happened on a water ride called Raging River. A raft carrying six people overturned on Saturday night at 7:30 p.m., with the park announcing on Sunday that one of the riders died.

“Adventureland is saddened to learn of the passing of one Guest involved in the Raging River accident on the evening of 7/3/21,” the Facebook post says. “This investigation is ongoing and the ride remains closed. Adventureland is working closely with both the State and local authorities, and would like to thank them again for their efforts. At this time, we ask for your thoughts and prayers for the Guest and their family, as well as for our team members who were onsite.”

According to USA Today, three people were taken to the hospital in critical condition and a fourth person was in non-critical condition. The ride had been checked on Friday, prior to the accident, and it appeared to be working completely fine.

Another person died from the ride before. In 2016, a 68-year-old staff member hurt himself when he was working on the ride, just a few days after starting his summer gig. He was assisting a rider out of a raft when he fell onto the conveyor belt, leading to a skull fracture and a major brain injury. He passed away four days later.