CTV News has learned the special reward for any information that may lead to the discovery of Lyle and Marie McCann has topped $50,000.

Just last week, the man who police once called a "person of interest" in the case of the disappearance of the couple was named a suspect in the case.

Police said the investigation is considered to be a suspicious missing person case in which they believe that the disappearance of the couple was a result of foul play. Investigators revealed Travis Vader is a suspect in the case.

Lyle and Marie McCann left for B.C. on July 3rd and have not been seen or heard from since.

The McCanns' burned-out motor home was found on July 5th near the Minnow Lake campground approximately 35 kilometres southeast of Edson. On July 16th, their green Hyundai SUV was located deep in the bush about 30 kilometres east of Edson near Carrot Creek.

Vader was arrested in mid-July on charges unrelated to the couple's disappearance. Vader was picked up by officers at a rural residence near Niton Junction.

Last month, Vader's sister told CTV News last month that she didn't believe her brother is capable of hurting anyone. Bobbi-Jo Vader admitted her brother had been dealing with serious drug problems in recent years, and said she was glad he is in custody getting some help.

Mounties have been questioning locals in Vader's hometown west of Edmonton about the man's actions on one particular day.

Sources in Peers, Alta. say police activity here in recent weeks has focused on a convenience store.

Sources tell CTV News that in the weeks since media first showed in the small town where Vader grew up, RCMP investigators have shown up to the store and have asked about the surveillance cameras inside.

Questions have also been asked about whether Vader purchased a phone card inside the store on July 8th.

The couple's children and the RCMP will hold a news conference Friday at 11 a.m.