Police said Elijah had disappeared from a north-end apartment of a family member overnight. Two volunteers, who were part of a massive search by police and the public, found the boy tucked away in the corner of the backyard of a nearby home without vital signs.
Security camera video showed Elijah pushing his way through two doors of the building at about 4 a.m. Temperatures had fallen to about -20 C. He was found about six hours later.
"You see the picture of that beautiful little boy with a nice smile and the video of the child going out into the cold ... it really is a tragic set of circumstances," Chief Bill Blair said.
Elijah's grandmother sobbed and hugged friends as she left her apartment Thursday afternoon.
"No, no, no," was all she could say through tears.
Her long-time friend and neighbour, Millie Dyer, said the family was distraught.
"He's very energetic and runs around all over the place," Dyer said moments before hearing of the boy's death.
"He's a very smart little boy."
Dyer said Elijah, whom she called "sweet," was over at his grandmother's place all the time and has two aunts who also live in the same apartment complex.
"When his mom has to work, Elijah is here. And he goes to daycare just down the street," Dyer said.
Family members, who notified police of his disappearance at about 7:30 a.m., said they had put him to bed Wednesday night and woke up to find him gone and the front door open, police said.
Officers on horseback, foot and in a helicopter searched for him , and police asked neighbours to search their yards, hallways and stairwells for the missing youngster.
"Obviously the police response was aggressive and massive," Insp. Frank Barredo said.
Pratatban Thurairajah, from the city's west end, was one of volunteers who helped search for the boy after hearing about the incident on the radio.
"I decided to come down to look for him, trying to find him," Thurairajah said. "I wanted to find the boy — trying to do my part."
It's not the first time a youngster has wandered out into the cold and died.
In December 2009, a seven-year-old Nova Scotia boy died in hospital after surviving two nights lost in the frozen wilderness. James Delorey had apparently followed the family dog into the woods.