RCMP call Travis Edward Vader, 38, a person of interest in the case of a missing couple from Alberta. (RCMP)Mounties spent much of the weekend following up on an estimated 150 tips in the case of a missing Alberta couple and a man sought in connection with their disappearance.

Police said many of the tips are from people who say they have seen Travis Vader, 38, who is described as a person of interest in the disappearance of Lyle and Marie McCann. The elderly couple haven't been seen since July 3.

Over the weekend, police fanned out across a rural area of Alberta, looking for anything that could lead them to the McCanns or Vader.

Crews also scoured land along the highway, looking for anywhere the McCanns might have pulled over on their journey.

Lyle, 78, and Marie, 77, were last seen July 3 when they left their home in St. Albert, headed for British Columbia.

Their motorhome was found burned to a shell on July 5.

Eleven days later their SUV, a Hyundai Tucson they were towing behind the motorhome, was found west of Edmonton.

McCann family hopeful

The McCanns' relatives have been waiting anxiously for news, on edge every time the phone rings with the possibility the RCMP are calling with news about the case.

Marie Ann McCann and Lyle Thomas McCann were last seen July 3. (RCMP)"I mean, there's all kinds of scenarios here one could imagine, and I try not to think about that," said their son, Bret McCann.

He said he refuses to consider the possibility his parents are dead.

"My dad is very resourceful," Bret said. "I think of them that they may be in the bush somewhere, but I think my dad — this has been quite awhile, but I think he'd be taking care of Mom and he'd be looking after himself out there. So that's what I picture."

Nicole Walsh, the McCanns' granddaughter, is also hopeful her grandparents will be found alive.

"I honestly do think we'll be together as a family," she said.

"Grandpa loves to tell stories and I think this is just another story in his life. We will talk about it. You know, I can't wait to hear him tell the story."

The Mounties have not publicly reported any progress in their search for Vader or the McCanns in recent days.

Investigators have been in touch with some of Vader's friends.

Vader has a criminal history dating back to 1995, when he was convicted of stealing a vehicle. He was wanted on outstanding warrants before being named a person of interest in the McCanns' disappearance.

Police have described Vader as dangerous and possibly armed.

Anyone who sees Vader is urged to contact RCMP rather than approach him.