CNN — The search continues for about 40 people still missing after a runaway train plowed into a 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 homes and buildings and forced nearly 2,000 people to evacuate.
Lingering fires and the risk of more explosions have impeded the rescuers' search for the dozens still missing, CBC reported.
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 company said in a statement. The train's engineer had "tied down" and checked into a motel.
The locomotive of the oil train was shut down after the departure of the engineer who had handled the train, which may have resulted in the release of air brakes on the locomotive that was holding the train in place, the company said in a statement.
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 CNN affiliate CTV she was working at a bar nearby and got off work 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 in town.
"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.
Resident Amanda Gabrielle said the train crashed on her birthday. She lost her dog, 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.
CNN's Umaro Djau, Jonathan Mann, Pierre Meilhan and Deanna Hackney contributed to this report.
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By Holly Yan and Emanuella Grinberg