It only takes seconds for creatures to appear after death with the intention to eat you.
As soon as we die, we start giving off volatile organic compounds, such as dimethyl sulphide, dimethyl disulphide and dimethyl trisulfide. These compounds attract a plethora of insects.
“If you’ve ever had a steak outside, how long does it take flies to get to you? They’re going to come really quickly,” said Dr. Gail Anderson, forensic entomologist at Simon Fraser University in Vancouver.
She specializes on insects that colonize dead bodies with particular focus on the amount of time that has elapsed since death.
Anderson said using insects to determine time of death largely depends on temperature. Insects are cold-blooded creatures and as temperatures increase, they develop quicker and if it decreases, they develop slower.
Anderson will collect insects from a corpse to determine at what stage the insect is through its life cycle and compare it to weather records. Using the weather records, she’ll be able to say how long that insect took to get to that stage in its life cycle.
“Maybe I’ll say the insects are five days old. So, the insects have been on this guy for five days. So, he’s been dead for at least five days,” said Anderson.
|Dr. Gail Anderson said insects are extremely important for determining time of death.
“If it’s after 72 hours since death, it’s pretty much the only medical way you can estimate time since death.”
She never gives a time of death.
“What I give is a minimum time that the insects have been there.”
The insects that are primarily attracted to a dead body are blow flies, the same ones that are attracted to meat in your garbage.
“They will come and lay eggs, those eggs will hatch into maggots and those maggots will eat you,” Anderson said.
“They’re the first witnesses to a crime.”
Later, flesh flies appear and as the body’s fat decomposes, beetles arrive.
There are only three fully certified forensic entomologists in Canada, including Anderson. One of which is Anderson’s former grad student and the other is a student she’s mentored. Both are in Ontario.
When Anderson was first offered a side job as a forensic entomologist, she thought she’d try it for a year to see how it went.
That was in 1988.
Now she’s a criminology professor, director of forensic research and has a suite of labs specifically for forensic entomology at Simon Fraser University.
When she first started in the 1980s, the subject wasn’t well known.
“I would get phone calls from police officers in nowheresville, somewhere. Who would say they heard insects were worth something. Is that true they would ask. Like someone has been kidding them.”
She’d say yes, it’s a recognized sign.
Today, studying insects is a normal part of police homicide investigations.
|Blow flies are the first witnesses to a crime. (Unsplash)|
Anderson said she works on cases from across the province, however she does not know specifics since she just gets a casefile number, without the name of the deceased or suspect.
She was also a key part of helping to exonerate an American woman locked up for nearly 17 years for a murder she did not commit.
In 2001, Kirstin Blaise Lobato was accused of stabbing a homeless man to death in Las Vegas, Nevada. The body was found behind a dumpster and the medical examiner estimated the time of death up to 24 hours prior. No one noticed absence of blowflies.
Lobato was sentenced to life in prison.
At no time during the trail or the second trail in 2006, did lawyers call on a forensic entomologist to clarify why there was no insect colonization on the body.
In 2009, Anderson got a call from the magazine Justice Denied to ask if she could help exonerate Lobato using forensic entomology. When Anderson heard there were no insects on the body, she knew something was wrong.
Although blow flies are typically the first insects to colonize a corpse, they do not fly after dark. Thus, time of death was determined to be wrong.
In 2017, a judge ruled Lobato’s lawyers were ineffective and failed to present forensic evidence, later the prosecution vacated the case and Lobato was released from prison.
The future of forensic entomology is continuing to evolve said Anderson and researchers are starting to look at the necrobiome, which is the community of organisms associated with a decaying corpse.
“There’s an intimate relationship between insects and bacteria,” Anderson said.
Insects will transfer bacteria from body to body and researchers are trying to determine how that impacts decomposition.
When one life ends, thousands more begin.
“It’s a complete ecology,” said Anderson.