Fire officials say not everybody who lives in a 35-unit Burnaby apartment complex that was gutted by fire early Sunday has been accounted for.

But assistant fire chief Darrell Smith said firefighters believe they were able to evacuate everybody in the building at the time of the fire.

"There may be some people on hoildays, who didn't come home last night -- we can't account for them," Smith said.

He estimated 35 families were displaced because of the raging inferno, which broke out at the apartment complex on Smith Avenue near Canada Way shortly after midnight.

Smith said the decades-old building wasn't up to code and it made battling the blaze much harder, leaving residents homeless because of it.

"There were no sprinkler systems, no standpipes," he said. "I've gotta really feel sorry for the people that lived here...Unfortunately for this apartment, it's probably going to be levelled."

The fire originated in the basement of the four-storey building before it crept up through the walls to the rest of the building, said assistant chief Ken Moore.

The complex didn’t appear to have a sprinkler system in place, he said.

When crews first arrived at the blaze, they had to rescue “numerous” people from the burning building before they could go to work extinguishing the fire, Moore said.

“Several victims were hanging out of the third and fourth-floor windows,” he said. It took several crews with ladders to evacuate them.”

More than 40 firefighters combated the blaze and searched for tenants before retreating from the building because of fears of structural collapse, Moore said.

“At this point we’re in a defensive mode and we’re trying to drive the fire to the rear of the building,” he said Sunday morning at the scene of the fire.

Residents trapped in the burning building described the mayhem as they attempted to get to safety.

“The whole place just filled up with this black, black smoke,” said resident Susan Walters. “You couldn’t breath, you couldn’t do anything.”

Witnesses reported seeing one couple jumping from the second floor to the ground below.

“He jumped, and then she threw the dog out and he caught their dog, and then she jumped out,” said Dennis Wilson. “He tried to catch her.”

Wilson, however, was not as fortunate and said his pets hid under the bed, making it impossible for him to get them to safety.

“I lose the three cats. I love everything,” he said. “What you see is what I have.”

Cynthia McPhee and her dog Creeky were among those rescued by firefighters.

“They’re awesome,” McPhee said. “They saved my life and everyone in that building. It was a pretty wicked fire.”

Several people were treated by BC Ambulance Service, but nobody was seriously injured, according to Moore.

Investigators have yet to confirm the cause of the blaze, but RCMP have deemed it suspicious and have taken over the case, according to Moore.

With a report from CTV British Columbia's Michele Brunoro