“He’s approached the collision scene, lost control on that quad bike and has collided with an 80km/h zone sign.”

Two motorcycle helmets were found at the scene, but it is not clear if they were being worn at the time of the crash.

Omar El Houli, the uncle of the two dead teenagers, said the extended family was having a party on Father’s Day before the crash.

“They’re beautiful kids, with absolutely beautiful parents,” he said. “It’s unfortunate what happened ... hopefully they’re looking down on us from heaven.”

Lineham said at a press conference the family had been unco-operative in answering questions from investigators. Around 50 people were at the property for the birthday party on Sunday.

He said the teenagers involved “should not have been riding” dirt bikes on Beattys Road in the first place, as it is an offence to ride without a licence on an unregistered motorbike on a public road.

“It’s a recipe for disaster. Unfortunately, these are the circumstances where people are out having fun of a nighttime... where you have dreadful [outcomes],” Lineham said.

“It’s always a highly distressing scene ... so you will expect heightened emotions at the time.

“If there’s kids on the bike, parents have got to look after these kids with correct riding equipment.”

Neighbour Tom Pandza said the crash occurred right on dusk, when the visibility on Beattys Road had dropped. He said there was a large gathering at the property throughout the day.

“They were having a bit of fun with the dirt bikes and quad bikes, but it was starting to get dark,” he said.

“I thought it was getting a bit dark to be riding at that stage, especially because the road here gets a lot of cars, which come through pretty quick.

“You do get a lot of cars speeding through here, and I actually worry for my kids when they go jogging down the road. I have to tell them to stay right off the road, on the nature strip.”

Pandza, who has lived on the road for 21 years, said the family involved had only recently moved into the house.

The narrow bitumen road where the collision occurs has a speed limit of 80km/h.

Speaking at the scene, Detective Sergeant Richard Wood said two young lives had been “tragically lost needlessly”.

“Motorcycles are not toys, they can be lethal weapons,” he said.

The major collision investigation unit is still working to figure out the exact circumstances of the collision and has appealed for witnesses, dashcam or CCTV footage.

Anyone with information or video can contact Crime Stoppers on 1800 333 000 or make a report online at www.crimestoppersvic.com.au.

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