Kevin, 55, Jennifer, 51, Robert, 19 and Cameron Dunsmuir, 16 all died inside their home in East Gwillimbury, Ont., about 50 kilometres north of Toronto early Friday.
Another son, David, 24, is the only remaining member of the immediate family. He was away at Brock University.
Both Robert and David had attended school in Newmarket, Ont., where hundreds gathered — only hours after finding out about their death — to mourn a much-loved family.
"They were such well rounded people," a peer of Cameron Dunsmuir told CBC News.
"It broke my heart."
Cameron was a football player halfway through his high school career.
Robert was a former major junior's hockey player, drafted by the Owen Sound attack.
"We are deeply saddened by the loss of Robert and his family” said Owen Sound Attack general manager Dale McGrey in a release.
"Our organization was stunned by the news. The Dunsmuirs were exceptional people and their deaths are an absolute tragedy."
The team took a moment of silence before their game on Friday.
Kevin Dunsmuir was a prominent lawyer in Newmarket and his wife Jennifer was just learning to walk again after a recent stroke.
"There were no better parents than Kevin and Jennifer," said Ashley Bailey, 16, a friend of the family.
On Saturday the town of East Gwillimbury announced they would make plans to provide assistance to the family and community affected by the loss.
The town lowered flags at all municipal buildings to show support.
"We plan to work personally with the family in the next few days to see what support we can provide that would be helpful to the family and the community in this time of grief," said Mayor Virginia Hackson, who knew the family personally.
The mayor also added that the town would show support to firefighters who were on the scene.
The Dunsmuir family was found together in a front room on the second floor of their home, where they had lived for many years.
"I don't know if there was an attempt to get out, I know they were together," said Scott Evenden with the Ontario Fire Marshal.
York Regional Police said that at 5:30 a.m. ET Friday they received a 911 call and were dispatched to the home on 72 Howard St.
Fire officials confirm there was a smoke alarm on the second floor and in the basement.