"I can tell you that we have met a lot of people....and what I can tell you is that about 40 people are considered missing," Quebec provincial police Lt. Michel Brunet said in the first news conference since the incident. "We have to be careful with that number because it could go up or down."
Police said two bodys were found overnight and another two Sunday morning. The first body was discovered on Saturday. Authorities say a higher death toll is "inevitable."
About 30 buildings were destroyed when tanker cars filled with oil caught fire at around 1 a.m. on Sunday. The severals blasts that took place throughout the night in Quebec's downtown area had hundreds of people, who where out since Saturday night, fleeing for their lives.
''I saw this on the international news yesterday [Saturday],'' Prime Minister Stephen Harper said. ''Everywhere people are talking about this. ''It's a beautiful downtown here that's been destroyed... There's really going to be a need for substantial reconstruction.''
Victims have been taking refuge in a High School near the derailment site which has been turned into the town's evacuee shelter.
Edward Burkhardt, the president and CEO of Rail World Inc., the parent company of Montreal, Maine & Atlantic Railway, told The Canadian Press the train was parked uphill of Lac-Megantic before it became loose and began careening downhill into town.
"If brakes aren't properly applied on a train, it's going to run away," Burkhardt said. "But we think the brakes were properly applied on this train."
"We've had a very good safety record for these 10 years," he added. "Well, I think we've blown it here."
Transportation Safety Board of Canada officials said Sunday that they have retrieved the train's black box and expect to use it to find out exactly what happened.
''It has data that captures things like throttle position, speed, time, distance, brake pressure,'' said Donald Ross, the investigator in charge.
''Where the train was left in Nantes, from that location down to Lac-Megantic is down a grade, and certainly the manner in which the train was secured, both air brakes and hand brakes, we'll be looking very strongly at that,'' he added.