07/16/2014 11:28 EDT | Updated 07/16/2014 11:59 EDT

Nathan O'Brien Missing: Green Balloons Fly Over Calgary In Tribute

Hundreds of green balloons were released into the sky across Calgary and Alberta Tuesday night in honour of missing five-year-old Nathan O'Brien and his grandparents, Alvin and Kathy Liknes.

Relatives, friends and community members gathered at a park across the street from the O'Brien home to release the balloons — a tribute that was repeated in communities across the province.

Nathan's mother and father, Rod and Jennifer O'Brien, wept and held each other and their son Luke as they watched the balloons fly away.

The balloon release was organized Monday after police announced that, based on evidence collected, the trio had been murdered.

"It's important the O'Brien/Liknes family is aware of the army of support they have standing behind them," said the group's Facebook page.

Meanwhile, a pile of flowers, stuffed animals and mementos has been growing on the front lawn of the Liknes' southwest home.

People across Canada have also tied green ribbons to trees and front staircases in support of the family.

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Nathan O'Brien, Grandparents Missing

Jennifer O'Brien told Metro Calgary she is holding out hope her son and parents are still alive.

Police have not shared the evidence from the case with her family, she said.

“They won’t tell us, but we do know that it’s not time for us to lose hope. I can’t and I won’t until we know for sure.”

Jeff Liknes, Jennifer's brother, told the Canadian Press he too has faith his parents and nephew may come home safely.

“I know the cops don’t really think so but I know my mom is really strong,” he said. “My parents were really strong. There’s just so much energy and so much life in them. If anybody’s going to make it through this it’s going to be them.”

The couple and their grandson dissappeared from their Parkhill home on June 29, after Nathan's mother dropped him off at the Liknes home for a sleepover.

Douglas Garland, 54, has since been charged with two counts of first-degree murder and one count of second-degree murder in connection with the case, though no bodies have been found.

Garland has ties to the Liknes family. His sister is in a relationship with a member of the Liknes family.

Court documents show Garland has a criminal record and mental issues.

In 2000, he was sentenced to 39 months for making amphetamines at his parents' farm. Before he went to prison, he jumped bail and lived for several years in Vancouver using the identity of a dead person.

The Parole Board of Canada gave him accelerated release after six months, noting in its decision that Garland's prior criminal record consisted of various property offences over the course of 20 years.

His mental health played a role in the crimes, the board said, but a psychologist determined that Garland had "little violence potential to others.'' It ordered a psychologist and psychiatrist to closely monitor him during his release.

He is scheduled to appear in court today.