Four people were killed on Tuesday in an accident at a popular theme park on Australia's east coast, officials said, according to AP. Two men and two women died while on a river rapids ride at Dreamworld, a park on Queensland state's Gold Coast, Queensland police officer Todd Reid told reporters. The Thunder River Rapids ride whisks people in circular rafts along a fast-moving, man-made river. A malfunction caused two people to be ejected from their raft, while two others were caught inside the ride, said Gavin Fuller, an officer with the Queensland Ambulance Service. He did not know if the two victims who were caught in the ride were trapped under water, or caught up in the machinery.