A suspect in the disappearance of a five-year-old Calgary boy and his grandparents will be charged with two counts of first-degree murder and one count of second-degree murder.

Police would not identify the suspect until he is formally charged, but CTV News has learned that Douglas Garland, 54, was arrested for the second time and there are no other suspects.

The bodies of Nathan O’Brien and his grandparents, Kathryn and Alvin Liknes, have not been found. But police said they now have enough evidence to conclude that they are dealing with a homicide investigation, not a missing persons case.

“The preponderance of evidence is such that it has led our investigators to believe that they are dead,” Calgary Police Chief Rick Hanson said Monday.

The first-degree murder charges relate to the Liknes couple and the second-degree murder charge will be laid in connection to Nathan’s death, Hanson said.

He said police are “optimistic” that they will find the bodies, “so the family can find closure on this.”

The Liknes and O’Brien families are “devastated,” Hanson said.

“I think it’s safe to say that even as the days went by, there’s always a hope. There’s always a glimmer of hope and unfortunately with the laying of charges, we’ve taken that hope away from the family.”

Police are asking the public to continue to come forward with any information about the case. Rural residents in the Airdrie area are also being asked to check their properties and notify police if they see anything suspicious.

Nathan and his grandparents were last seen two weeks ago, when the boy was visiting his grandparents for a sleepover. When his mother arrived to collect him the next morning, the three family members were gone.

Until recently, police had to assume that at least one of them was being kept alive somewhere, Hanson said.

But that changed Sunday afternoon, when investigators compiled all the evidence and met with the Crown prosecutor.

“The decision was reached that this is now a homicide investigation and charges would be appropriate against the accused individual,” Hanson said.

He said the investigation has been “painstaking.” It involved “meticulous” searches of a rural property near Airdrie, Alta., and two municipal landfills. Police also received about 900 tips.

“This file has been built piece by piece by piece,” Hanson said. “There is no single piece of evidence that would be what people would like to think is the smoking gun.”

Douglas Garland was questioned in connection with the missing family in early July after being arrested on an unrelated charge.

He was re-arrested sometime Monday morning after he was asked to leave a local hotel. Garland had been staying at the hotel as part of bail conditions stemming from an unrelated charge.

Garland was released on $750 bail last Friday, after he appeared in court on the unrelated charges.

Police have confirmed that Garland has a connection to the Liknes family. His sister is in a relationship with a Liknes family member.

Mayor, PM offer condolences

Calgary Mayor Naheed Nenshi issued a statement Monday offering his condolences to the victims’ families and thanking police for their work on the case.

“I, like all Calgarians, am terribly saddened to learn about the murder charges that were laid today related to the missing persons investigation in our community,” he said.

“My heart goes out to the Liknes and O’Brien families, and I know that they will continue to have the support they need from all of us at this very difficult time. My thanks go to my colleagues at the Calgary Police Service and the women and men of the RCMP for their hard work on this investigation.”

Prime Minister Stephen Harper also tweeted that he and his wife, Laureen, are “saddened by the tragic news from Calgary.

“Our thoughts & prayers are with the O'Brien & Liknes families during this time,” he wrote.