Two men and two children were killed when a light plane crashed into mangroves.
The four-seater aircraft crashed shortly after taking off from Redcliffe airfield, north east of Brisbane, about 9am.
The 69-year-old male pilot was one of the four people who died in the crash.
A man and two children who are not yet in their teens died in the crash. Police do not believe they are related to the pilot.
The pilot's family were at the Redcliffe Aerodrome when the crash happened, according to Inspector White.
He told media that it was a family day. The family are traumatised.
White said the families became aware of what had happened when the aircraft did not return.
He said it was a tragic accident. This is the last thing any family needs to go through at this time of the year, and it is the lead up to Christmas.
He said the flight appeared to have been pre-arranged.
A multi-agency operation is under way with water police officers and divers along with the forensic crash unit assisting other agencies, including the Australian Transport Safety Bureau, as investigations continue. Nine News and the Australian Broadcasting Corporation.
Water police and forensic divers worked at the scene of the crash as the plane was seen floating upside down.
The Australian Transport Safety Bureau is working to understand what caused the crash.
Air traffic control was yet to confirm the plane's movements, despite early reports that it went down after takeoff.
We will get any evidence we can from the plane itself, but also from other sources such as air traffic control and witnesses.
He asked witnesses or people with relevant information to contact the police.
The tide had gone out and it was difficult to get a barge in to recover the wreck.
The tide is going out, so I think it is ankle deep water.
At the time of the accident, it was slightly deeper.
Police and divers were confronted with a difficult situation.
The plane is in a very difficult situation in the wetlands, and we have police and divers travelling to that area, and that's all I can say at this time.
