QUEBEC, CANADA (CNN)--Authorities said they hope to search more areas Monday for about 40 people still missing after a runaway train plowed into an eastern Canadian town, setting off massive explosions when the train's haul of crude oil ignited.
At least five burned bodies have been found, but "we know that there will be many more" deaths, Quebec provincial police Lt. Michel Brunet said Sunday.
The 73-car train destroyed the downtown area of Lac-Megantic, Quebec, on Saturday. The crash and series of explosions flattened dozens of houses and buildings and forced nearly 2,000 people to evacuate from the town 130 miles east of Montreal.
Lingering fires and the risk of more explosions have impeded the rescuers' search for the dozens still missing, the Canadian Broadcasting Corp. reported. One place deemed too unsafe to search is Musi-Cafe bar, which was destroyed in the crash and was believed to have had customers at the time, CTV reported.
Firefighters are working to put out hot spots, and authorities hope doing so will let them search Musi-Cafe and other areas Monday, Quebec provincial police Sgt. Benoit Richard told reporters.
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"There has been a lot of work that's been done on the scene during the night, and hopefully we will get more areas that we can search during the day. But that of course is under the firefighters' responsibility," he said.
Canadian Prime Minister Stephen Harper described the town as a "war zone."
"There is not a family in this area that is not touched by this," Harper told reporters after touring the destruction Sunday.
Brunet said police are investigating whether foul play was involved.
"Right now, we cannot say that it is a criminal act. We only can say we are looking at it as if it was," the police spokesman said.
How did this happen?
The company responsible for the train said an engine shutdown may have released air brakes holding the train in place.
The train had stopped for a crew change Friday night in a station about seven miles from Lac-Megantic, the Montreal, Maine & Atlantic Railway said. The train's engineer had "tied down" and checked into a motel.
Investigators with the Transportation Safety Board of Canada found the locomotive event recorder and planned to analyze it for information on throttle position and speed, among other data.
Balls of shooting flames
Witnesses told CBC they heard five or six explosions. One person saw the train's first oil tanker tip over and yelled "run, run!" as he dashed toward a lake. He told CBC the flames chased him to the edge of the water.
"The fire was moving so quickly," he said. "We saw balls of fire shooting out onto the water."
One woman told CTV got off work at a nearby bar an hour before the accident.
"I have no news from my friends; I haven't heard from any of them," she tearfully told CTV. "I can't say more than that. We're waiting for confirmation."
Families and friends are scrambling to find the missing
More than 17,000 people have joined a Facebook page to help people connect with their loved ones in the town.
Multiple posts ask about Guy Bolduc, a singer who was performing at Musi-Cafe.
"All of his fans, all over Quebec, but also his fellow singers (of whom I am one) hope to see him again alive!!! Come on my GuyBol, come out of your hiding place," one member wrote.
Residents struggled to absorb what had happened to their small lakeside community.
"It's dreadful," Claude Bedard told CBC. "It's terrible. The Metro store, Dollarama, everything that was there is gone."
Authorities evacuated more than a third of the town of 6,000 people, most from the center of the town and a home for the elderly.
Amanda Gabrielle said the train crashed on her birthday. She lost her dog and her home, and doesn't have any family or friends nearby.
"I lost everything," Gabrielle told the CBC. "I don't know what's going to happen to me."