Police are appealing for the public's help identifying a van connected with the double homicide of a couple found on the side of a highway in northeastern British Columbia as grieving families plan to travel from Australia and the United States.

RCMP Sgt. Janelle Shoihet said it's not known if a blue 1986 Chevrolet van with Alberta licence plates belonged to either Lucas Fowler, 23, or his girlfriend Chynna Deese, 24, a resident of Charlotte, N.C.

Fowler, who is from the Sydney area of Australia, was living in B.C., and Deese was visiting him, Shoihet said. Their bodies were discovered Monday along the Alaska Highway, also known as Highway 97, about 20 kilometres south of Liard Hot Springs.

"If you were in the area, if you have dash cam video, we're asking you to get in touch with investigators," Shoihet said, adding police are particularly interested in speaking with anyone who was travelling along the road that is a throughway to Alberta, Yukon and Alaska after 4 p.m. on Sunday or after 8 a.m. on Monday.

"This is tragic," Shoihet said, adding police do not know whether the pair was targeted or died in connection with "a crime of opportunity."

Shoihet would not say whether the couple's bodies were found inside or outside of the van.

"Our hearts and thoughts go out to all the families involved and friends internationally and here nationally as well because Lucas was living here," she said. "We are working with our partners internationally in order to advance this as best as we can."

The RCMP says in a news release that Fowler's father is an active member of the New South Wales Police Force who is travelling to Canada with a number of police officers from Australia.

"These investigators are here in support of the Fowler family and will not form part of our investigative team here in Canada," the release says.

A statement from Fowler's family was posted on the website of the New South Wales Police Department.

"We are all now travelling to Canada to be with our boy and to bring him home," the statement says, describing Fowler as a dear son, brother, grandson and friend.

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

"To know his beautiful girlfriend, Chynna Deese of Charlotte, North Carolina also lost her life in this violent event is too cruel."

Shoihet said the "unique" crime is not believed to be linked with any other incidents.

A statement posted by Deese's sibling, Kennedy, said the North Carolina family was "in shock and heartbroken."

The Zeta Tau Alpha at Appalachian State University in Boone, N.C., said Deese was one of its members, and an obituary posted by her family remembers her as a "kind and adventurous soul."