Last summer, Gabriel Rusk was over the moon.

On a fishing trip with his family in Alaska, the 13-year-old caught his first halibut, all on his own.

"He was just beside himself, so excited, so proud,” remembers grandpa Ken Walters.

The boy's father, Brad — also beaming with pride — caught the whole moment on camera.

The recording is now one of the many happy mementos the family is holding onto as they struggle to come to terms with the tragic death of Gabriel, Brad, 45, his wife, Valerie, 37, and their daughter, 11-year-old Rebakah.

The family was found dead last Sunday, along with their friend and boarder Donald McNamee, 47.

Though blood tests are currently being conducted in Vancouver, officials have said deadly carbon monoxide is likely to blame.

When firefighters arrived at the Porter Creek home, carbon monoxide levels were 10 times the amount that would be picked up by a standard home alarm.

The tragedy has left families on opposite ends of the country reeling.

"I think we are all still in shock,” Walters told the Star today from his Alberta home. "It seems very unreal.”

The proud grandfather said his daughter Valerie was a fun-loving and cheery mom, who, along with her husband, shared a love of the outdoors with their young children.

During visits to Whitehorse, Walters remembers setting up his trailer to camp.

Next to him, Valerie set up a pup tent and cooked over a wood stove.

"That was camping to her,” he says. "They spent as much time in the great outdoors as they could.”

Both Brad and Valerie grew up in Alberta, and met while working in the central Alberta town of Drayton Valley.

The family moved to Whitehorse in 2005 to fulfill a life-long dream of Brad's to live in the North. At the time of his death, he was working for the Yukon government.

"They loved it there; they were very happy,” Walters said. "There was so much for everyone to do.”

Their parents' love of the outdoors appears to have been successfully passed on to the two Rusk children.

Described as "a princess” by her family, the youngest Rusk child liked wearing dresses and doing anything girly.

But Rebakah was also brave and more than willing to camp and play outside in the dirt with her brother, Walters said.

Though they could fight just like ordinary siblings, the pair generally got along well, he says, often playing video games together.

Gabriel was just getting comfortable at Vanier Catholic Secondary School, where he was in Grade 8.

"He flourished there,” Walters said. "He was really happy and doing really well.”

In Ontario, McNamee is being remembered as a person who loved to laugh, smile and was always willing to help out a friend.

In fact, that's why he was living in the Porter Creek house where he died, according to his family.

Brian McNamee said his younger brother moved in with the Rusks to help out after Bradley experienced some health issues about a year ago.

"He wasn't just a boarder, they were friends,” McNamee said from his home in Markham, Ont.

A cook by trade, the younger McNamee most recently worked for the territory's Wolverine Mine.

Like so many others who find their way to the Yukon, the 47-year-old free spirit had lived around the country, including in Calgary, Vancouver, Winnipeg and all through Ontario.

He arrived in the Yukon four or five years ago and immediately felt at home, his brother said.

"He loved it there, he put down roots.”

Brian McNamee said he read about the deaths of five people in Whitehorse in the newspaper Monday before finding out that his brother was one of them.

"I'm reading this article thinking, ‘My heart goes out to this family,' and that night the police come to tell my mother,” he said.

The coroner released his brother's body to the family Tuesday night. Funeral arrangements have yet to be finalized.

Both families say their loved ones never expressed any concerns to them about the house's heating system.

Officials with the fire marshal's office said Tuesday their investigation has turned to the oil-fired boiler system used to heat the 1960s-era home on Centennial Street.

In the midst of the tragedy, both McNamee and Walters encourage others to make sure they have carbon monoxide detectors in their home.

Fire officials have said the home did not have a warning system.

"Make sure you get them,” McNamee said. "Make sure you test them; they are so important.”

Meanwhile, Valerie Rusk's colleagues at Assante Financial Management are planning a celebration of life for all five to be held at at 2:30 p.m. Saturday at Vanier Catholic.

A fund for the families has also been set up at the Bank of Montreal.

As well, friends are setting up an account to accept donations in honour of the families to go toward Whitehorse General Hospital's new MRI.

More details on this account are expected to be released tomorrow.