LAC-MEGANTIC, Quebec (REUTERS) - Investigators sifted through the charred remains of Lac-Megantic's historic downtown early Wednesday morning, as they searched for clues into what could turn out to be North America's worst railway disaster since 1989.
Police said they are investigating whether Saturday's derailment and subsequent explosion - which levelled the centre of the lakeside Quebec town killing at least 15 and probably dozens more - involved foul play or criminal negligence.
"We are conducting a criminal investigation. We are not neglecting anything so far," provincial police inspector Michel Forget told reporters on Tuesday evening.
He added that some 60 officers would continue to work through the night gathering evidence and searching for remains.
Canada's Transportation Safety Board said it was looking into whether the train's operator - Montreal, Maine and Atlantic - followed proper safety procedures in the hours before the unmanned 72-car train carrying crude oil rolled down a hill and slammed into town.
The incident forced some 2,000 people, or roughly a third of the town's population, to leave their homes and seek shelter in local schools or with friends and family.
As firefighters contained the blaze, many of the evacuees were allowed to return to their homes, where they found a mix of relief, emotional distress and unexpected problems.
"After that tragedy, after watching that fire burn half the downtown, we are happy to be back home," said Denis Leveille, 57, who spent the day on his front porch visiting with friends.
"But we're not really settled in, because we don't have electricity right now. Our only power is that yellow cord there," he said, pointing to an extension cable running out a front window and across the yard to a neighbour's house.
"We need that for the fridge and the coffee maker - so we have coffee in the morning and beer at night."
But others were not as lucky. With parts of the town still considered dangerous - and part of it still a crime scene - emergency officials could not say when the remainder of the evacuees, about 800 people, would be permitted home.