Grieving Fowler family arrives in Canada

Peter Mitchell, AAP US Correspondent
Lucas Fowler's family has arrived in Canada after his murder alongside girlfriend Chynna Deese

The heartbroken family of murdered Australian tourist Lucas Fowler, who was shot dead alongside his girlfriend in a remote part of Canada, has arrived in the country as local authorities vow to look at all leads to solve the murders.

Mr Fowler, 23, from Sydney, and his girlfriend Chynna Deese, 24, from North Carolina, were found dead last Monday about 750km away on the side of the Alaska Highway after their blue 1986 Chevrolet van broke down.

His father, NSW Police chief inspector Stephen Fowler told Nine News while transiting at Los Angeles airport that Lucas was "just a wonderful boy".

"He's a loss to so many people. And his girlfriend also - it's just devastating. And our heart goes out to the whole of her family," he said.

"We are just crushed."

Two NSW homicide detectives also travelled to Canada to help as liaisons.

The Fowler family is expected to meet Royal Canadian Mounted Police investigators in British Columbia for an update.

Road worker Alandra Hull has told Nine News she saw Mr Fowler and Ms Deese on the highway the night before they were found dead, talking with a man who "kind of looked frustrated or something".

She said the man was standing in the middle of the highway, while Mr Fowler and Ms Deese stood beside their van.

"If you just get a bad feeling, and that's what I had, you just don't stop," she said.

Adding to the mystery, the body of a man was found on Friday near a burning pick-up truck south of the Stikine River Bridge on Highway 37 in northern British Columbia.

"Northern BC is a really big area and yet they don't have a lot of these events," RCMP corporal Chris Manseau told AAP on Saturday.

"Two of them have happened within a couple of days of each other and people want to speculate.

"The last I heard there was nothing to tie either of those two together although investigators are looking at all of the leads."

The RCMP have released few details about the Stikine River Bridge death and the shooting deaths of Mr Fowler and Ms Deese.

They have hosed down speculation a serial killer might be the perpetrator.

Mr Fowler and Ms Deese were on a Canadian road trip last Sunday on the Alaska Highway, 20km south of Liard Hot Springs, when their old van broke down.

Passing motorists saw them, including Canadian couple Curtis and Sandra Broughton who stopped to offer assistance about 3.20pm on Sunday.

Mr Broughton, a mechanic, said he spoke to Mr Fowler but the young Australian seemed to know how to fix the van.

"The vehicle was flooded out and they were going to try and get it going again until they could get the parts they needed," Mr Broughton told AAP.

The Broughtons got back in their car and drove home. Mr Fowler and Ms Deese were found dead the next day.

Trevor Pierre, a road worker and paramedic, went to the scene and saw the pair lying near their van after tourists raised the alarm, Nine News reported.

"I don't know how anyone could live with themselves after doing what I saw," he said.

RCMP investigators want to speak with anyone who may have been travelling near Liard Hot Springs on Alaska Highway 97 between 4pm Sunday and 8am Monday.

They are particularly interested in motorists with dashboard cameras who may have been filming.

RCMP would also like to speak to anyone who was staying at camping sites in the area.