The man police have called a "person of interest" in connection with the disappearance of a Calgary family was charged with identity theft this past weekend related to a decades-old case.

Douglas Garland, who was taken in for questioning from a rural Airdrie property on Friday, has a criminal history, including drug trafficking and possession of stolen property after he was caught making amphetamines on his parents' Airdrie acreage in 1992. 

Police took Garland into custody for questioning related to the search for five-year-old Nathan O'Brien and his grandparents, Kathy and Alvin Liknes, and CBC News has learned police have charged him with stealing the identity of Matthew Kemper Hartley — a 14-year-old Alberta boy killed in a car crash in 1980.

Police Nathan car

Police released this photo of a Ford truck on Friday as the investigation continued. (Calgary Police Service)

After failing to appear at court in 1992 for drug charges, the then 33-year-old Garland disappeared.

A document from the Tax Court of Canada indicates Garland was later discovered living under Hartley's stolen identity in Vancouver.

The same document says Garland suffers from attention deficit disorder and had attended medical school in Alberta for one year before suffering a mental breakdown.

Garland told the court at the time he had been traumatized after causing what he described as a horrific accident after falling asleep behind the wheel.

Garland returned to Calgary after being discovered living in Vancouver and pleaded guilty to several of the charges in connection to the drug bust and stolen identity, while the others were dropped.

While Garland had already confessed to stealing Matthew Hartley's identity in the 1990s when he was hiding out in Vancouver, the new charge laid this weekend relates to the recent use of that same identity and allows police to keep him remanded in custody until at least tomorrow.

CBC News learned Garland was released from questioning specifically in regards to the Nathan O'Brien disappearance, but remained in police custody in relation to the new charge of identity theft laid against him this weekend.

On Monday, Garland will make a court appearance related to his new charge of identity theft.

Garland has not been named as a suspect in the disappearances.

CBC News has also learned that Garland has a connection to the Liknes family through his sister.

His sister lists Nathan O'Brien's parents, Rod and Jennifer, as well as Kathy Liknes as 'friends' on Facebook.

She also lists one member of the Liknes family as a niece.

New search area blocked off

Earlier Sunday, police blocked off a new search area at a rural property northeast of Calgary and brought in the canine unit to help with the investigation into the disappearances of three Calgary family members.

Around 2:45 p.m. MT, investigators blocked off a new site north of the rural Airdrie property where they have been searching for clues since Friday night. The field has a large body of water and a police helicopter has been seen hovering over the water over the course of the afternoon.

Several officers and a dog are currently in the field.

Kathryn Liknes, Nathan O'Brien and Alvin Liknes

Kathryn Liknes, from left, Nathan O'Brien and Alvin Liknes were reported missing last Monday. (Calgary Police Service)

Investigators say the size of the property makes it likely their search may not wrap up until sometime Monday.

They seized a vehicle from the property that they say is similar in description to the one captured on CCTV images released Friday but can't confirm whether the vehicle is the same one in the photo or whether it is even linked to the case at all.

Police say they are still trying to determine whether Garland, the property, or the vehicle they seized at the property on Saturday, are linked to their investigation.

Neighbours tie ribbons of hope to homes

O'Brien and his grandparents were reported missing on Monday morning after Nathan's mother arrived to pick up her son from a sleepover at the Liknes's Parkhill house. The family had been over throughout the weekend helping out with an estate sale the Liknes's were holding ahead of a planned move to Edmonton.

Parkhill residents are now tying ribbons to their homes in a symbol of hope and support for the missing family members.

The Parkhill Stanley Park Community Association says the ribbons are meant to increase awareness and express hope for the safe return of Nathan and the Likneses.

Over the past two days, volunteers have been distributing green ribbons to people in the area to tie to the front of their homes.

At a news conference Saturday evening, Duty Insp. Joel Matthews with the Calgary Police Service said investigators had not found Nathan or his grandparents during the search, which is why the Amber Alert issued almost a week ago remains in effect.

During a shoulder-to-shoulder search in a field at the property, Matthews says a white flag was put in place at a site in the field but he could not comment on what that means.

Matthews said they received a tip Friday night that led them to investigate the property but he couldn't say what gave the tip weight.

"We want to make sure we cover off every avenue," he said.

Police still seek anyone at estate sale

Police are still looking to speak with anyone who attended the Liknes's estate sale on June 27, 28 and 29. 

Investigators estimate between 200 and 300 people went through the home over the course of the weekend but they are trying to get an idea of what was purchased and what remains in the home.

They say there was no sign of forced entry into the home but that blood found inside confirms that a violent incident did take place there.

Police could not say who the blood belonged to, only that whoever it was from would have been "in medical distress."

The forensics unit also examined "marks" along the outside of the house but police could not confirm whether those marks are blood.

Police say they have a number of theories so far as to what took place but they aren't making those public.

Anyone with information about the case can call the Calgary Police Service at 403-266-1234 or Crime Stoppers anonymously at 1-800-222-8477.

With files from the CBC's Meghan Grant