Police are investigating whether speed was a factor in the horror crash in Perth that left three young men dead.
An Audi A3 driving west and blue Kia driving east on the same road in Baldivis collided just after 5pm yesterday.
The driver of the Audi and father of two Jaziah Thomas, 24, father of two Kody Bell, 24, and his brother William, 21, were killed at the scene.
A fourth man, 21, was seriously injured and taken to hospital.
The 44-year-old woman driving the Kia had minor injuries.
Acting Inspector Brendon Barwick said yesterday the scene was very confronting for first responders.
Detective Senior Sargeant Adam Matson said losing three young members of the community in one crash is "hard to comprehend".
He said police will be looking at speed and a number of other factors in what caused the crash.
"There's some suggestion that not all occupants may have been wearing seatbelts at the time of the crash," he said.
Thomas' partner Tamekah Locker posted a tribute on Facebook for the love of her life and the amazing dad to their children.
"It still doesn't feel real and I keep waiting for you to just walk through the door and it breaks me apart to know you're not going to," she said.
"You have been my whole world, my best friend and my person since we were 14 and I don't know how I can live without you, I just want you to come home.
"You were the perfect partner and perfect dad we are so lucky to have had you in our lives and we will never forget you and all of our memories."
William's friend also posted a tribute to Facebook about his big heart and sense of humour.
"You (were) one of a kind with the biggest heart and best sense of humour and being one of a kind," the friend said.
"Willy not a day will go by that (you're) not in our thoughts as well as Kody, may god love and protect your family."
Matson said the investigation may take a number of weeks.
