"We're not sure why both aircraft were on the same trajectory or why they were in that area, but unfortunately they've collided mid-air", Victoria Police Inspector Peter Koger told ABC News.
"There were some people in the paddocks at the back of this facility and there was also a helicopter in the air and we're working with them to get witness statements", he said.
The Australian Transport Safety Bureau sent investigators from Melbourne, Canberra and Brisbane to the crash site and said they are looking at "human factors, aircraft operation and maintenance" as possible causes.
The planes were not incinerated but have hit the ground hard, Insp Koger said.
The ATSB is appealing for any witnesses who saw the planes in flight or who have dash-cam footage to contact authorities.
Hospital president dies of infection in Wuhan
New cases rose by 1,886 to a total of 73,335, according to Centres for Disease Control data collated by Johns Hopkins University . A study among tens of thousands of confirmed and suspected cases showed that 81 percent of patients had only mild infections.
Football Moment that Left us Speech-Less.
With an 11- 0 score at the end of the game, Germany started the Shanghai Women’s World Cup with a world record win. Women’s World Cup 2007 Germanys women’s team opened the World Cup with a bang against Argentina.