THE CANADIAN PRESS -- WINNIPEG - An overnight fire in a Winnipeg rooming house that killed four people appears to have started near the front entrance and would have blocked the path for anyone trying to escape, the city's deputy fire chief said Saturday.

Reid Douglas said the blaze started outside the north-end home on the veranda, with the front of the structure on fire when firefighters arrived.

Three people were outside the home and told rescuers that more were still inside.

"It actually had started to go up the stairs. The stairs are virtually inside the front door, so the heat would not allow people to escape,"Douglas said. "They'd have to be going out windows or back fire escapes or whatever, if they were even aware of it."

Firefighters went in through the back of the home and brought six people out. Four have since died and two others are in critical condition in hospital.

All of the victims were adults.

Police said arson and homicide investigators are probing the blaze.

Douglas said it's been years since there has been a fire at a Winnipeg rooming house that resulted in multiple deaths. Over the past few years, he said the fire department has targeted rooming houses for safety inspections, and the one that burned overnight was inspected June 6.

There were a few small infractions that were found, he said, but he noted they were corrected by the time of the follow-up inspection three days later.

Douglas said the fire alarms in the home were working and that investigators had to switch them off when they entered.

He added that it appears some of the victims suffered smoke inhalation.

"Unfortunately, it looks like this was the perfect storm and circumstances prevented people from exiting the home. Plus the timing, at 2 a.m., doesn't allow for a lot of people being awake," he said.

Douglas said there's nothing so far to link the fatal fire to recent fire-bombing activity connected to a biker gang turf war in the city.

"I know there's been a report of a lot of gang violence in the city. But the preliminary investigation doesn't seem to indicate that there's anything to that effect. The investigation will certainly bear that out, though," Douglas said.

"It could be an accident or it could be deliberate. I don't know."

On Friday, Winnipeg police announced they will go door-to-door to warn neighbours of known gang members as part of an attempt to crack down on a biker gang turf war that has seen more than a dozen buildings firebombed or shot up in recent weeks.

Police believe two rival gangs are battling over control of the city's drug trade and are trying to intimidate each other by attacking homes or businesses connected to each other's members or affiliates. Police have not named the gangs, but they are believed to be units associated with the Hells Angels and Rock Machine.

In most cases, there have been no injuries, but an exchange of gunfire July 4 left a 14-year-old boy wounded.

Arson investigators were also looking into two other early morning fires in Winnipeg on Saturday. In one, police said the front of a home was set on fire, while the other involved a blaze in a suite. No one was injured in either of those fires.