07/14/2014 01:35 EDT | Updated 07/14/2014 06:59 EDT

Douglas Garland Arrested, Murder Charges Pending In Missing Calgary Family Case

Calgary police say two charges of first-degree murder and one charge of second-degree murder are pending in the disappearance of five-year-old Nathan O’Brien and his grandparents, Alvin and Kathy Liknes.

Chief Rick Hanson says a man has been arrested but he can't identify him because the charges have not been officially laid.

Hanson says bodies have not been found, but an Amber Alert issued shortly after the group was reported missing has been cancelled.

"Evidence has led us to believe they are dead," Hanson told reporters.

However, he said that there is no single piece of evidence – no "smoking gun" – that led to the arrest of the suspect. Instead, investigators have been working for the past two weeks on a "putting a very complex case before the courts."

Earlier Monday, Douglas Garland, a man who police had previously questioned in the case of a missing Calgary family, was taken back into police custody.

It is unclear whether he is facing new charges or why he was arrested.

Hanson offered his condolences on behalf of police to the Liknes and O'Brien families Monday.

"There's always a glimmer of hope and unfortunately with the laying of the charges we've taken that away from the family," said Hanson. "They're devastated."

Calgary Mayor Naheed Nenshi also tweeted his condolences.

Nenshi continued his remarks in an emotional statement:

"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. 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 offered his support to the families:

The family haven't been seen since June 29 after what police say was a violent incident in the Liknes home.

Nathan was at his grandparents' for a sleepover and when his mother arrived to pick him up the next morning everyone was gone

Garland is the only person of interest identified in the case. Police spent more than a week searching his parent's acreage in Airdrie, where he has been living.

Police are still asking people near the Airdrie farm to check their properties and to call them if they note anything out of the ordinary.

Garland has ties to the Liknes family. His sister is in a relationship with a member of the Liknes family and he had business dealings with Alvin Liknes as well.

Garland had been questioned on the disappearance and arrested on an unrelated charge involving identity theft.

Garland was released on bail last Friday.

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