Couple and their grandson, Nathan O'Brien, disappeared June 29
Police say they will sweep the property of Alvin and Kathy Liknes as part of a three-pronged attack Saturday, searching for more clues.
The couple and their five-year-old grandson, Nathan O'Brien, disappeared from the home on June 29.
Police say there is evidence a violent crime occurred there.
Searchers also continue to comb the rural property of person-of-interest Douglas Garland near Airdrie, north of Calgary, as well as several surrounding acreages.
Police are also sifting through mounds of garbage at a northwest Calgary landfill.