Police have now recovered a total of 15 bodies from the Lac-Megantic train disaster, with dozens of people still missing.

As police announced the recovery of two additional bodies Tuesday afternoon, they said criminal negligence will be considered as a possibility in the ongoing investigation.

“Criminal negligence might be one of the leads that we’re looking at, as much as others,” Insp. Michel Forget said during a news conference.

He wouldn’t elaborate on why the investigation was being considered criminal.

The death toll from the train derailment now stands at 15, and around 35 are still missing.

Forget said 200 officers will be dedicated to the investigation – the largest in the Quebec’s history-- and much of the downtown core remains a crime scene.

The death toll rose as the Transportation Safety Board said local authorities were never alerted that the runaway train carrying shale oil was heading toward Lac-Megantic.

The TSB is conducting its own investigation into the derailment.

TSB investigator Donald Ross said rail dispatchers had no opportunity to intervene as the train hurtled towards the town and set off a series of explosions.

"There were no signals nor track circuits, so the rail-traffic controller had no -- and would have had no indication that there had been a runaway train," he said during a news conference Tuesday.

These alert systems are located on busier rail lines, but not on secondary lines, TSB manager Ed Belkaloul said.

The TSB also said that the train was travelling much faster than its authorized speed.

"Although we can't provide the precise speed at this time, the train was travelling well in excess of its authorized speed at that point. The locomotive detached from the rest of the train and carried through the rest of the town and out the other side, approximately six-tenths of a mile," Ross said.

He outlined the chain of events that led up to the disaster, saying the train first stopped in Nantes, Que., about 13 kilometres away. A fire was reported on the train just before midnight, which firefighters extinguished.

Then, just before 1 a.m., after the fire crew and the train engineer had left the scene, the train started moving downhill towards Lac-Megantic.

He said there are about 14 TSB officials on site to determine what happened, and how similar accidents can be avoided in future.

Meanwhile, the head of the company which owns the derailed train, Edward Burkhardt, arrived in Montreal Tuesday evening en route to Lac-Megantic.

Burkhardt maintained his earlier claims that the fire department in Nantes played a role in the disaster.

He told reporters that his company “certainly” feels a responsibility for the incident.

He also said he will be meeting with municipal officials in Lac-Megantic, to discuss how the company can contribute to the town’s recovery.

Company that owns derailed train was regularly inspected: Transport Canada

Officials from Transport Canada said Tuesday that the company which owns the train that derailed was regularly inspected and monitored.

Director general of rail safety Luc Bourdon said Montreal, Maine & Atlantic Railway (MMA) was subject to Transport Canada’s regulations and faced a number of inspections on its cars, crossings and tracks last year.

“We’re monitoring them same as any other company,” he said during a news conference Tuesday afternoon.

He added that the train was inspected the night before the derailment and no deficiencies were found.

During the news conference, Transport Canada officials faced a barrage of questions over the reported chain of events leading up to Saturday’s disaster.

Questions about operating procedures, hand-brake requirements, the strength of the tanker cars carrying the cargo and the minimum number of crew members required to man a train were lobbed at the officials.

According to Transport Canada, there are no regulations on the specific number of handbrakes that need to be applied, as each train varies according to its model, length and weight.

Instead, each time a train stops it is required to perform a test to ensure the train doesn’t move after the brakes have been set.

As well, it confirmed that the tanker cars were not double-hulled, as Transport Canada does not require crude oil to be transported in reinforced tankers.

The train was operated by a one-man crew: the engineer who was reported to be at a hotel at the time of the blast.

When asked how common is it in Canada to leave a train unmanned for the night, as the MMA train was reported to be, Bourdon said it was “very unusual” but does not violate any regulation.

He denied allegations that the number of safety inspectors had been cut, saying that there are 101 safety inspectors and 35 inspectors for hazardous goods.

Gerard McDonald, assistant deputy minister of safety and security, said he was extending his “deepest condolences” to the devastated community.

McDonald said Transport Canada is fully cooperating with the TSB as it continues its investigation and will be looking at ways to increase safety.

Residents allowed to go home

Earlier Tuesday more residents of Lac-Megantic were being allowed home for the first time after firefighters said fires are now under control.

Sgt. Benoit Richard of the Surete du Quebec said about 1,200 residents are being allowed to return to their homes Tuesday. One area is still considered unsafe for residents to return to, however.

Around 2,000 people were originally evacuated from their homes after the derailment.

A boil-water advisory is still in place in the community, though the measure is considered preventative .

Soil quality is also considered to be within safe levels, though residents who see evidence of oil on their property should use soap and water to clean up the remnants, or go online for more information about dealing with oil contamination.

The blast occurred early Saturday after the parked train's brakes apparently failed in Nantes, Que., about 13 kilometres away, sending the train careening downhill towards Lac-Megantic. It derailed in the town and caught fire, which in turn led to several explosions.

The train was carrying 72 tanker cars full of shale oil en route from North Dakota to Saint John, N.B.

Ross said the TSB has been advocating for stricter rules and regulations for "wagons" or tanker cars used to transport flammable products.

With files from The Canadian Press