NOJACK, Alta. - RCMP have concluded combing a campground west of Edmonton in their hunt for a couple missing for almost three weeks.

Sgt. Tim Taniguchi says investigators felt it was necessary to search the area near Nojack, which is not far from where police arrested a person of interest in the case earlier this week.

But he can't say what — if anything — was found because the investigation into the whereabouts of Lyle and Marie McCann continues.

"I can tell you the investigation is continuing and if evidence was found then it would have to be processed through our forensic processes...

"The perception that some members of the public have that this could happen very quickly, in reality, forensic evidence processing can take a significant amount of time."

Taniguchi also says Travis Edward Vader is now in custody at the Edmonton Remand Centre.

He says the 38-year-old has been questioned by officers with the major crimes unit, but details of the interview can't be released either.

The McCanns, both in their 70s, were last seen July 3 when they gassed up their motorhome in their home town of St. Albert, just north of Edmonton, before heading to B.C. for a family camping trip.