The son of an elderly Alberta couple that vanished on their way to a camping trip in British Columbia is pleading for help from the public to find his parents.

Lyle and Marie McCann of St. Albert, just outside Edmonton, were reported missing by their family on July 10, two days after they were due to meet their daughter in Abbotsford, B.C., for week-long camping trip. The couple was scheduled to make various stops along the Yellowhead Highway en route.

Mounties say a Gulf Stream RV belonging to the couple, who are both in their late 70s, was found burned to the ground on a dead-end road near the Minnow Lake campground near Edson, Alta., a week ago.

RCMP said at the time they believed they were just dealing with a burned motor home and did not connect the incident to the couple's disappearance until a missing persons report was filed at an Alberta detachment.

At a press conference in Edmonton Tuesday their son, Bret McCann, held up a picture of a small SUV the couple were towing behind the RV that is now missing.

"We really need to find this SUV," he said, adding the family had not heard from the couple since July 3.

McCann said his father, a retired long-haul trucker, was very familiar with the mountainous terrain between Alberta and B.C., and he and his wife frequently travelled to the U.S. for fishing and camping trips in their motorhome.

"This motorhome was my dad's pride and joy," he said. "We had every comfort...they would travel on this trip and they would be fine. They were in their late 70s but they were quite vigorous."

Mounties confirm there were no human remains found inside the RV. The vehicle the McCanns were towing, a Hyundai Tucson with Alberta licence plate ZPK 289, has not been seen.

The couple's family has set up a Facebook group in an effort to gain any information that might aid the search.

Serious crime investigators returned to the campground Tuesday aided by search and rescue volunteers to sweep the area for evidence.

"Right now what we're doing is (re-examining) the scene where the vehicle was found burned," Sgt. Patrick Webb said. "We're working with the family trying to determine all the possible stops the people may have made."

Bret McCann said his whole family is praying for the couple's safe return.

"We're hopeful the public can help find our parents," he said

"Our whole family is just devastated by this. It's unbelievable really."

Police say there has been no record of the couple using their bank account or making phone calls since they were last heard from by family on July 3.

With files from The Canadian Press