Police continued searching around a body of water on an Alberta property Monday as they look for clues about the mysterious disappearance of a five-year-old boy and his grandparents.

Police have been at the property northeast of Airdrie since Friday, with dozens of officers combing through fields, sifting through sheds and searching a nearby body of water. Both a canine and a helicopter unit were on the scene Sunday, as well as a zodiac boat, but police wrapped up their search shortly before the dinner hour.

The property is on Range Road 291 north of Highway 567, northeast of Calgary.

Police resumed their search at the property early Monday.

Meanwhile, investigators questioned and released a man they describe as a “person of interest” in the case. Police have not identified the person of interest, but CTV News has learned that his name is Douglas Garland. His parents own the property where police are now searching.

Police say the man is not a suspect in the investigation, but he remains a person of interest. No charges have been laid against him in connection to the missing persons’ case.

Both the property and Garland are known to police.

In 1992, police discovered a drug lab on the property. While police did not find finished product, they did find the elements needed to make illicit drugs, CTV’s Alberta Bureau Chief Janet Dirks reported Monday.

Garland was charged but skipped town and settled in British Columbia, where he lived for seven years under an assumed name. According to court documents, Garland assumed the identity of a teen who had died in a car crash.

Garland appeared in court Monday on charges of obtaining and assuming someone’s identity with the intent to commit an indictable offence, Alberta Bureau Chief Janet Dirks reported. The charge appears to be unrelated to the missing family, police said. They would not confirm whether Garland remains in custody for the unrelated identity charge.

Garland had also attended medical school in Alberta for about a year, but dropped out after suffering a breakdown, according to court documents.

An Amber Alert has been in place since 5-year-old Nathan O'Brien and his grandparents, 66-year-old Alvin Cecil Liknes and 53-year-old Kathryn Faye Liknes, were reported missing on June 30.

Nathan had been staying with his grandparents at their Calgary home over the weekend, and was reported missing when his mother went to pick him up on Monday and found an empty house.

Police arrived at the Airdrie property on Friday after receiving a tip about a green Ford F-150 pick-up truck parked on the property. A similar truck was spotted on surveillance footage near the Liknes home.

It also appears that there is a connection between Garland and Nathan’s parents and grandparents. Garland and members of the O’Brien and Liknes families share many of the same Facebook friends. Nathan’s father, Rod O’Brien, would not comment Sunday on the apparent connection.