Statements from various players in the events that led to the disaster pointed Monday to a possible dispute about what happened and who's to blame.
The main antagonists in that disputed chain of events are a rail company and the municipal fire department in a town next door to now-decimated Lac-Megantic.
The fire chief in Nantes said he can't believe a train was left running and unattended in the hours before the disaster, when it had already just been in flames.
Patrick Lambert said his team had been trained by the Montreal, Maine & Atlantic railway to handle fires on its line — and that it had intervened to fight four fires on the company's trains in the last eight years.
He said a resident called late Friday to report a fire in the locomotive, with flames leaping out from the chimney. A dozen firefighters intervened to put out the blaze in Nantes, which is about 10 kilometres up a slope from Lac-Megantic.
That same train eventually rolled down into Lac-Megantic, derailed, and exploded into balls of fire, killing at least 13 people and leaving nearly 40 more missing.
Lambert said that when his crew had intervened, the engine was shut off as per the standard operating procedure dictated by MMA. The blaze was extinguished within about 45 minutes.
And that's where the fire department's involvement ended, he said.
"The people from MMA told us, 'That's great — the train is secure, there's no more fire, there's nothing anymore, there's no more danger,'" Lambert told reporters.
"We were given our leave, and we left."
The case is now being probed by the federal Transportation Safety Board, as well as the provincial police.
The rail company tells the story differently.
Edward Burkhardt, the president and CEO of the railway's parent company Rail World, Inc., suggested Monday that the fire crew didn't do enough — and even suggested that the decision to shut off the locomotive to put out the fire might have disabled the brakes.
"As the air pressure deflates, they (the brakes) will become ineffective and an hour or so after the locomotive was shut down, the train rolled away," Burkhardt told the CBC on Monday.
While the fire service in Nantes has said it left the train in the care of a track-maintenance employee, Burkhardt said it's possible that person might not have known how to secure the brakes.
"When they get a call about a locomotive having a fire, why did they not rouse the engineer (from bed) and take them out there with them?" he asked.
Burkhardt appeared to downplay his company's role in the disaster: "Is any of this huge negligence? No, you can't point to that."
He did not return repeated calls and emails Monday. Burkhardt had said in a weekend interview with The Canadian Press that the brakes had been properly applied by the company, and he defended its safety record.
However, the U.S. Pipeline and Hazardous Materials Safety Administration reports eight incidents related to dangerous products with MMA since February 2005.
There were two derailments within several days in June near Lac-Megantic, including a spill of 13,000 litres of diesel. The company was also fined $30,000 by the U.S. Environmental Protection Agency over a 2009 leak that contaminated a river in Maine.
MMA has drawn much of the anger from locals and the perception that it has been less than responsive since the disaster.
Complaints about the company have ranged from lack of visibility, to old concerns about safety, to the fact that a press release written in French appeared sloppily translated and loaded with errors.
The company insists its representatives have been on-site since the weekend, and that Burkhardt will be in Lac-Megantic on Tuesday.
Transport Minister Denis Lebel declined to comment on the policy of leaving trains unattended. He said the government would have more to say after receiving an investigation report.
"I don't want to say that it's the normal practice," Lebel told reporters in the town, "but it's their (MMA's) practice."
Lebel confirmed that the train that exploded had been inspected in Montreal the day before the tragedy. He said the inspection revealed no anomalies.
He also defended Canada's train-safety record, following criticism over the weekend by Opposition Leader Tom Mulcair. The minister said train accidents in Canada are actually down, significantly, in recent years.
The other main opposition leader, the Liberals' Justin Trudeau, toured the site Monday and declined to offer policy lessons from what he described as a horrific event.
"I'm blown away, obviously by the terrible destruction ... but also by the strength and the courage of the people who have come from across the country to help out," Trudeau said.
"It's still too early to try to formulate theories on why or how it happened. Today and for the coming days, we will be occupied with residents, families who lost everything in certain cases, to help them and support them."
But Lambert, the Nantes fire chief, did draw some policy lessons from the disaster.
He said the surge in oil transportation by rail has been noticeable on the tracks — where he said just a few years ago there might be three or four tankers in a larger convoy but now entire trains are loaded with one fuel tanker after another.
Lambert called that dangerous and urged rail companies to leave other cargo, or empty boxcars, between tankers to help limit the "explosive" domino effect.
Amid Lac-Megantic's massive blast zone, eight more bodies were found Monday.
The number of those pronounced dead rose after investigators managed to gain better access to the spots closest to the blast.
The first bodies were found on the weekend and the coroner's office said they were being examined in Montreal to determine their identity.
The coroner's office asked relatives of people missing to provide DNA — through a toothbrush, for instance — to help identify victims.
Everyone is preparing for grim news.
Jean-Pierre Tetrault, a doctor whose cottage is about 20 kilometres away, said he called the local hospital Saturday as soon as he got news of the tragedy and offered to help treat the wounded.
He was told there was no one to treat. There were only a few people suffering from smoke inhalation.
He took that as a disheartening testament to the impact of the blast; he said it suggests that "those who were in the explosion stayed there."
"It's a very bad sign," he said.
The town began its work week Monday in anything but working order.
Dozens of businesses and numerous homes are destroyed.
A grocery store, a dollar store, and a popular downtown bar are gone. So is the municipal library. There's a no-go zone around city hall and a main pharmacy.
The town's prized veterans' park, along the water, has been scorched.
After viewing the devastation Sunday, Prime Minister Stephen Harper likened the downtown of Lac-Megantic to a ''war zone.''
From England, the Queen offered her condolences Monday for what she described as a shocking loss of life. She said she hoped it would be possible to rebuild both the property and the lives affected.
The epicentre of the disaster was a now-obliterated bar where many people are feared to have died.
Sophie L'Heureux, manager of Le Musi-Cafe, left the bar Friday at around 10 p.m. to go home for a quick nap. She was supposed to return to the pub later in the night.
"I'm in survival mode right now. My priority is to try sleep if I can, eat if I can," she said Monday. "For the rest, it's one minute, one day at a time."
"(I) have lots of trouble sleeping because I'm stuck with the images and the sounds, the noise of the fire. It's very difficult to get away from that."
Her home is close to the bar, so the ray of light from he crash woke her up. She went outside and saw the flames.
"I saw enough to be horrified by what happened."
She lost three colleagues and many friends and acquaintances at the bar. L'Heureux was the manager for about a year, but had worked and hung out there regularly for the last several years.
She expressed an enormous amount of anger toward the railway company — a feeling shared by many residents Monday.
L'Heureux said the company can't possibly repair all the damage that's been inflicted.
About 30 buildings were destroyed, including Le Musi-Cafe where partygoers were enjoying themselves in the wee hours of a summer night.
The multiple blasts after Saturday's derailment of a train carrying crude oil sent people fleeing in the municipality of 6,000, about 250 kilometres east of Montreal.
The prime minister has promised to draw lessons from the conclusions of the ongoing Transportation Saefty Board investigation in the incident to prevent a repeat of such a tragedy.
Federal TSB officials said they planned to interview all possible participants as part of what they called a "360-degree," top-to-bottom, investigation.
They said they had retrieved a so-called "black box" from the train Sunday.
-With files by Melanie Marquis, Paola Loriggio and Peter Rakobowchuk
Also on HuffPost