Calgary police have called in a plane to assist with the ongoing search for three people missing and presumed dead.

In a statement released Saturday, the city of Calgary said police have partnered with the National Research Council of Canada in the ongoing search of a rural property in Airdrie, Alta.

An acreage near Airdrie has been the subject of a massive police search after five-year-old Nathan O'Brien and his grandparents, Alvin and Kathy Liknes, went missing from the Liknes home in Calgary nearly three weeks ago.

"As part of the ongoing search of a rural property in Airdrie, the Calgary Police Service has partnered with the National Research Council of Canada to utilize their equipment to assist in the search," the statement said. "An NRC plane will be flying over the property throughout the weekend."

Earlier this week, police charged Douglas Garland with two counts of first-degree murder and one count of second-degree murder in connection with their investigation into the disappearance of the Calgary family.

The bodies of the victims have not been found, but Calgary's police chief says investigators have evidence they are dead.

Property near Airdrie, where Garland lived with his elderly parents, is where police have focused their search. On Friday, divers also searched a pond near the acreage.

As the search continues, police continue to ask private landowners and businesses to check their rural property for anything suspicious.