Tokyo Dome City, Tokyo, Japan -

A guest at Tokyo Dome City, 34-year-old Fumiaki Kuranouchi, fell to his death last Sunday while riding the Spinning Coaster Maihime with a friend. Shortly after the ride began, he was reportedly thrown from the coaster onto the concrete twenty feet below. After the fall he was rushed to the hospital, but was declared dead just two hours later. He and his friend were visiting Tokyo Dome for the Monster Hunter “stamp rally.” The park has since suspended all ride operations.

Spinning Coaster Maihime is a compact spinning wild mouse coaster designed by Maurer Sohne, and with each car seating four riders back-to-back in twos, and spins as it negotiates tight turns along the track. According to Kuranouchi’s friend, the pair were worried they may not be allowed to ride since they are both “big” (Kuranouchi was 6’ tall, 285 lbs), and had been thinking about getting their Monster Hunter stamps and returning home if they could not ride, but both were allowed on the ride.

The part-time worker responsible for operating the ride said she didn’t do a hand-check to ensure the safety bar had been locked as it “appeared to be locked as it was positioned right on his stomach.” Though several others were working at the ride to guide passengers on and off of the ride, she was solely responsible for the rides operation. She told the Yomiuri Shimbun that “at the time of the accident I was looking at a staff assignment sheet, so I didn’t monitor the roller coaster operation at all.”

Since the event, police have gone through the parks offices “on suspicion of professional negligence leading to the death,” as well as the offices of Suginami Ward, the firm that imported and sold them the coaster. Investigators are also suspicious that the park’s training manual does not show how to confirm safety bars are locked--employees are instead verbally told to do so. The police there are investigating whether it was the fault of the rider, who may have failed to follow safety instructions, or the female operator, who could be charged with professional negligence pending the investigation.

Just three years ago, back in 2007, the Fujin Raijin II coaster at Osaka’s Expoland derailed, killing a 19-year-old female who hit her head on the guardrail and injured 19 others. That investigation revealed that the cause of the accident was a cracked axle which hadn’t been replaced in 15 years, and the park was closed permanently in 2009.

Tokyo Dome is also home to LaQua amusement park, which has the Intamin hypercoaster Thunder Dolphin, known for its rooftop-crossing bunny hills, and the Big O, the parks giant hubless Ferris Wheel. Tokyo Dome President Shinji Kushiro offered condolences to the Kuranouchi family, but has not confirmed when the park would reopen after the incident.