The moment four people were killed in a horrific accident on the Thunder River Rapids ride at Dreamland on the Gold Coast was captured on CCTV.
Police said they would be scouring the video to determine exactly happened to cause the deaths of four people when one of the ride's rafts flipped, trapping two people between the conveyor belt and drowning another two.
Two young children who were also in the raft were thrown free during the capsize but watched helplessly as their parents were killed.
The four people killed in the tragedy have been identified as Canberra mother Kate Goodchild, 32, her brother Luke Dorsett, 35, and his partner Roozbeh Argahi, 38, as well as 42-year-old Cindy Low, believed to be a New Zealand expat.
The 12-year-old daughter of Ms Goodchild and the 10-year-old son of Ms Low were thrown from the raft during the capsize and watched on helplessly as their mothers were killed.
The husband of Kate Goodchild rushed to help his wife but was unable to save her.
It was originally reported that his wallet had been stolen from Mr Goodchild's pram during the incident but 7 News has now been told the items were apparently taken for safe keeping by a police officer or paramedic and have since been returned.
Assistant Commissioner Brian Codd told media Wednesday morning that if he was thankful for anything, it was the survival of the two young children.
"It seems almost a miracle that anyone came out of that," he said.
"If we are going to be thankful for anything, I’m thankful of that."
Asked how the two young children survived Commissioner Codd said it must have been "through the providence of God".
“The fortunate thing here is the two children managed to escape that disaster, and unfortunately the four adults did not,” he said.
Paramedics and park staff tried in vain to perform a rescue, but it soon became a recovery operation.
Mr Araghi worked at the Australian Bureau of Statistics in Belconnen, Canberra.
In a statement, the Bureau described Mr Argahi as a hardworking member of the communications team "who brought joy and fun to the workplace".
Witnesses watched in horror as some of the victims were thrown from the raft, and two others were caught inside the ride.
The ride, which had been a functioning part of the park for 34 years, had broken down twice before the accident and was closed last weekend, but passed a safety inspection to re-open.
Witness Claire Wooley told 7 News she saw a young girl screaming for her mother while waiting with a friend, later confirmed to be her father, to go on the ride.
“We believe she was on the ride, I don’t believe she was in the same raft but we do understand it was her family involved and she was screaming for her mother,” she said.
Lia Capes, who was waiting with Ms Wooley saw people screaming and running from the ride in hysterics after the incident.
“We had come for a fun day and unfortunately this was how it had to end,” she said.
The heartbroken mother of Ms Goodchild and Mr Dorsett expressed her grief on Facebook following the tragedy, saying: “My family have been completely wiped out.”
“I have three children and two of them are now gone," she wrote. “My eight-month-old granddaughter is never going to know her mother and that truly breaks my heart."
She told the Courier Mail her 12-year-old granddaughter, who witnessed the accident, was "devastated" and struggling to come to terms with what happened.
"She is going through unimaginable pain at the moment. I’m at a loss as to how to deal with this now."
Investigators are examining CCTV of the incident and drone footage to help determine how the tragedy unfolded.
In a statement released late on Tuesday, the park announced it would remain closed indefinitely.
"Our immediate concern now is to support the families of the victims and to provide appropriate counseling to our visitors and staff," it read.
"We are working closely with authorities to understand exactly what occurred.
"Dreamworld is closed until further notice."
The park's CEO Craig Davidson said he would be working closely with investigators.
“We are deeply shocked and saddened by this and our hearts and our thoughts go to the families involved and to their loved ones,’ Mr Davidson said.
Commissioner Codd said the tragedy deeply affected the not just the family and friends of the victims, the Gold Coast community, and Dreamworld staff, but also first responders, police, paramedics and other emergency services who attended the incident.
“This is having a deep and emotional effect for a lot of people,” he said.
“We were called to one of those jobs you just don’t expect to happen. Coming to a place where a families want to come and enjoy each other’s company and just have fun doesn’t really equate to such a tragedy that we have seen."
A full and lengthy investigation is expected, to examine what led to the catastrophe.
"We owe it to the deceased and their families, we owe it to the community of Queensland to get to the bottom of what caused this," Commissioner Codd said.
"To hold accountable any person that needs to be held accountable for this occurring, but most particularly ensuring that this can never happen again."
“It is absolutely vital that we get to the bottom of all aspects of this very complex tragedy.”
Gold Coast Mayor Tom Tate has paid tribute to those who were killed at the theme park.
He said, “This is a very sad day for our city. Our thoughts are with the families of those affected and the emergency staff in attendance."
"I urge everyone to show the respect needed as the relevant authorities undertake investigations in to what has occurred. A truly sad day for all.”
Queensland Police confirmed it was a "workplace incident". They were called to the site at Coomera around 2.20pm following reports that a number of people had been injured by a conveyor belt.
Emergency crews including seven ambulances attended the scene.
Prime Minister Malcolm Turnbull has said he was saddened to learn of the tragedy.
“Theme parks are a place for family fun and happiness, not tragedy. This is a very, very, sad, tragic event. Our thoughts and prayers are with the families of those who lost their lives,” he said.
“This is a very sad day, and we trust there will be a thorough investigation into the causes of this accident over the days to follow.”
The theme park disaster has been compared to 1979’s Sydney Luna Park Ghost Train inferno, which killed six children and one adult.
One of Australia's most popular theme parks, Dreamworld will remain closed indefinitely following the tragedy.