An Australian man and his American partner are believed to have been murdered in Canada’s British Columbia.

The Royal Canadian Mountain Police is treating the couple’s deaths as suspicious, and NSW Police this week sent two homicide detectives to Canada.

Lucas Fowler, who is the son of NSW Police Chief Inspector Stephen Fowler, and Chynna Deese were found dead on the side of the Alaska Highway on Monday in the province of British Columbia. 

“We have lost our dear Lucas Fowler, son, brother, grandson, and friend in the most terrible of circumstances,” the family said in a statement to NSW Police. 

“To lose someone so young and vibrant, who was travelling the world and just enjoying life to the full, is devastating.”

The family also paid its respects to Lucas’ girlfriend Chynna Deese. 

“All our love and best wishes go to Chynna’s family and friends,” they said.

“We are all now travelling to Canada to be with our boy and to bring him home.

“Our deepest thanks for all your love and care. At this stage, we can only move forward a minute at a time, and those minutes are moving so slowly.”

Two NSW homicide detectives have been sent overseas to assist the investigation, liaise and support family members.

“The investigation into this incident is being led by the Canadian authorities and as such, they will be the appropriate source for information as it comes to hand,” the police statement said.

The Royal Canadian Mountain Police is treating the young couple’s deaths as suspicious. 

The Department of Foreign Affairs and Trade is assisting the family.

“The Department of Foreign Affairs and Trade is providing consular assistance, in accordance with the Consular Services Charter, to the family of an Australian man who died in Canada,” a spokesperson said in a statement.

“Due to our privacy obligations, we will not provide further comment.” 

Canadian police said an old blue minivan was found at the scene and police are looking for anyone who saw the vehicle or can offer assistance.

They’re also appealing for anyone that travelled the stretch of highway around the time of the discovery to come forward, according to an RCMP media release.

– with additional reporting from AAP