CSI Lac-Mégantic: How are victims identified after a disaster?

On July 5, 2013, tragedy struck the town of Lac-Mégantic in Quebec. A train pulling 72 tank cars full of crude oil derailed. This created a huge explosion. Then a fire destroyed part of the downtown area. It took firefighters nearly 40 hours to put it out. Forty-seven people lost their lives.

Did you know?

In most Canadian provinces, the Royal Canadian Mounted Police (RCMP) handles forensic investigations. In Quebec, it’s the Laboratoire de sciences judiciaires et de médecine légale (LSJML). In Ontario, it’s the Centre of Forensic Sciences (CFS).

What made the Lac-Mégantic fire different from a typical fire?

The Lac-Megantic fire was very different from a typical house fire. Usually, firefighters get house fires under control fairly quickly. It usually takes them between a few minutes and a couple of hours. 

When people die in house fires, it’s usually not from burns. Most victims are killed by carbon monoxide (CO) poisoning due to smoke inhalation. Carbon monoxide is a component of smoke. It’s a result of incomplete combustion. 

So if someone dies in a house fire, the body usually isn’t badly burned. This makes it easy to identify the person.

But in the Lac-Mégantic fire, victims’ bodies burned for many hours. Most of the flesh (muscles and fat) was reduced to ashes. If any flesh remained, it was because of the position of the body. In most cases, only bones were left. This made it difficult to identify the victims.

The material that fuelled the Lac-Mégantic fire was also very different. Most house fires are fuelled by wood and other building materials. But the Lac-Mégantic was fuelled by the crude oil in the derailed tank cars. This made the fire even more destructive, both to the town and to the victims’ remains.

Who helped to identify the victims?

Once a deadly fire is put out, forensic workers start trying to identify the bodies. Several types of forensic workers help investigate a crime scene. And they use various methods of forensic science to identify victims. Let’s learn about some of these workers and the methods they use. 

Forensic pathologists are medical doctors. They determine a victim’s cause of death by performing an autopsy. 

Forensic anthropologists study human remains, especially bones. Using a full or partial skeleton, they can determine a victim’s sex, age and cause of death.

Forensic odontologists are scientists who study the teeth of victims.

Did you know?

Forensic science has many branches. They include toxicology, podiatry, optometry and botany.

The Lac-Mégantic disaster was massive. The crime scene was huge. So was the number of victims. But forensic scientists used the same methods as they do to investigate any murder or suspicious death. 

How do forensic scientists analyze badly burned remains?

Forensic scientists have several ways of identifying badly burned bodies. 

To determine a victim’s sex, forensic anthropologists mainly look at the skull and pelvis. Female skulls are usually smaller than male skulls. And female pelvises are typically wider than male pelvises. That’s because a woman’s pelvic opening needs to be large enough for a baby to pass through.

Forensic anthropologists can look at bone fusion to determine a victim’s age. Bone fusion is a process that occurs in the human body as it ages. Over time, bones often begin to fuse, or knit, together. For example, the fusion of the epiphysis (end) of the humerus and femur bones could indicate a victim’s age. 

Forensic scientists might also look for medical implants, such as artificial hips. Each medical implant has a unique serial number. This serial number will be in a database, along with the name of the person who received it. 

Forensic odontologists can compare dental records and dental remains. They will look at the size of a victim’s jaw, the number of teeth, and the position of the teeth in the jaw. This can help identify the victim.

Forensic scientists can also use DNA to identify a victim. DNA can be extracted from the bones or even the badly burned flesh of a victim. Investigators will then ask the family of a missing person for an object with the person’s DNA. For example, a person’s toothbrush normally contains some DNA. The two sets of DNA are then compared to determine if they match.

Did you know?

Forensic scientists don’t need a person’s full genome sequence to identify a victim. Instead, they look at 13 unique segments, called short tandem repeats (SRTs).

Finally, personal objects sometimes survive even the most intense fire. For example, investigators might find a victim’s wallet. Of course, these objects can lead to false identification. But they can be helpful and practical starting points for identifying a victim. 

To confirm a victim’s identify, forensic scientists need to use at least two of these methods. And the two methods need to give the same result. 

The Lac-Mégantic investigation took a long time. During the first two weeks, only 22 of the 47 victims were positively identified. They mainly used DNA analysis and dental records to identify these people. 

It’s important to remember that forensic investigations can be very difficult. Forensic professionals do incredible work. But sometimes even they can’t identify bodies that have been severely damaged. 

Did you know?

Three train workers were accused of criminal negligence causing death in the Lac-Mégantic rail disaster. In 2018, they were found not guilty.