Marie McCann, 77, and Lyle McCann, 78, left Alberta for B.C. on July 3 and have not been seen by their family since. ((RCMP))

The family of Lyle and Marie McCann is raising money so they can offer a reward to anyone whose tip helps solve the Alberta couple's disappearance in early July.

"We're hoping that if there is a reward that it will encourage someone, somewhere, to come forward with that information to help us complete this puzzle," the couple's son, Bret McCann, told reporters at a news conference in St. Albert, Alta., Monday.

Lyle, 78, and Marie, 77, were last seen at a gas station in their hometown of St. Albert on July 3. The couple was planning to drive their RV to British Columbia where they were planning to meet their daughter.

Two days later, the couple's motorhome was found on fire at the Minnow Lake campground near Edson, about 200 kilometres west of Edmonton. Their light green Hyundai Tucson SUV was found in the bush near Edson on July 16.


The couple's son, Bret McCann, speaks at a news conference in St. Albert, Alta., on Monday. ((CBC))

On July 19, RCMP arrested a man whom they called a person of interest in the case, but no charges have been laid against anyone in relation to the couple's disappearance.

Over 20 investigators are working on the case, RCMP Sgt. Tim Taniguchi said. Progress is being made on the case but Taniguchi said he couldn't go into more detail.

"That would be part of the investigation and I would not want to taint the investigation at all," he said.

The reward amount has not yet been determined. So far, the fund sits at $11,000, with all but $1,000 coming from an anonymous donor.

The money will go to anyone who passes on information that leads to the discovery of the McCanns and the arrest and conviction of the person or people responsible for their disappearance.

Crimestoppers accepts anonymous tips, but anyone wishing to claim the reward would have to identify themselves and speak to investigators directly, though their name would not be released to the public.