A woman killed with her three children after colliding with a bus on Sunday night near Kambalda in the WA Goldfields was returning from church in Kalgoorlie.
The mother, her two daughters, aged nine and seven, and her 12-month-old son died after their Hyundai Getz hit a Hino bus carrying mine workers about 30 kilometres south of Kalgoorlie-Boulder just before 7pm.
Kalgoorlie Acting Superintendent Rod Wilde told Radio 6PR's Paul Murray on Monday it appeared one of the vehicles had gone to the wrong side of the road.
"We are working through it - obviously we are still asking for any witnesses to come forward, but we are getting an idea what occurred," he said.
"It was pretty horrific weather over the weekend and the roads were wet and it's a dark area there."
Acting Superintendent Wilde believed the family was heading home after church.
He said no-one on the bus was injured.
"Fortunately the driver and four passengers and were not seriously injured there," he said.
Acting Superintendent Wilde said it was a dangerous stretch of road.
"Generally because of the high speed and lots of bends on it," he said.
"I can say in the five years I've been here there hasn't been an another fatality, but certainly there has been some serious crashes on the road."
He said major crash investigators would prepare a report for the coroner.
"Our major crash people from Perth are in charge of the investigator and the Kambalda and Kalgoorlie police are assisting them," he said.
