Alberta RCMP are trying to find a welder who may have information in the case of two missing seniors.
Lyle and Marie McCann, both in their 70s, were last seen July 3, 2010, as they gassed up their motorhome in their hometown of St. Albert, just outside Edmonton. They were heading out on a road trip to British Columbia.
The burned RV was found two days later 200 kilometres west of the city. Soon after, an SUV they had been hauling was discovered in thick bush in the same area.
Investigators want to talk to the person who modified a tow bar on the couple's Hyundai Tucson so it could be hitched to their Gulf Stream Voyager RV.
Sergeant Tim Taniguchi said it's not a key part of the case, and the welder is not a suspect. But officers want to pin down the information.
"They've tried to firm it up through other means, talking with local welders, hitch companies," Sgt. Taniguchi said Thursday.
"They've been unsuccessful at this point. That's why they've gone to this length to ask for the public's assistance to see if it twigs any memories from welders or employees in the hitch business."
He said investigators have received more than 2,000 tips in the disappearance and at least six officers continue to work on the case.
"I can stress that we are making progress … and it continues to be a priority."
An Edmonton court last year granted an order declaring the couple dead so that the family could process their wills and deal with their estate.
A letter from the RCMP, submitted to the court, declares the couple was murdered, although the bodies have not been found.
Travis Vader is the only person police have named as a suspect in the case, although he has not been charged.
Vader, 39, was recently sentenced to 33 months for unrelated property crimes. He remains in custody because he still faces a trial in April on another set of property charges.