LOCARD’S EXCHANGE PRINCIPLE by Michael Rigg

Edmond Locard (1877-1966)

No doubt, you’ve seen or heard the saying, “Take only memories, leave only footprints.” It’s a shorthand way of telling humans to minimize their impact on nature. If you see something, leave it for someone else to see and enjoy. If you eat a Milky Way, don’t throw away the wrapper. Take it with you.

What a wonderful sentiment. What an exceptional goal. But to those of us who write mysteries, especially those involving crimes, it’s sheer, absolute, and utter nonsense. Pure baloney. Leave only footprints? Give me a break.

Those of us “in the know,” accept the “Gospel According to Dr. Locard.” Developed by Dr. Edmond Locard (1877 – 1966), Locard’s Exchange Principle, which forms the foundation of forensic science, holds that the perpetrator of a crime will bring something to the crime scene and will leave with something from it. At its core, the concept is that every contact leaves a trace and that with contact between two items, there will always be an exchange. To quote Dr. Locard, “It is impossible for a criminal to act, especially considering the intensity of a crime without leaving traces of this presence.”    

Think about it. It makes sense.

Wherever a criminal (or even a totally innocent, law-abiding citizen) goes, he will leave something behind. At the same time, he will also take something back with him. Our criminal (or law-abiding citizen) can leave all sorts of evidence, like fingerprints, footprints, hair, skin, blood, bodily fluids, pieces of clothing—and more. By coming into contact with others, or things, at the location in question, our criminal (or law-abiding citizen) takes part of that location with him when he leaves, whether it’s dirt, hair, or other types of trace evidence.

During an investigation in 1912, a Frenchwoman named Marie Latelle was found dead in her parents’ home. Her boyfriend, Emile Gourbin, claimed he had been playing cards with friends on the night of the murder. Absent evidence to the contrary, police concluded Gourbin was telling the truth.

Not deterred, Dr. Locard looked at Marie’s corpse and questioned Gourbin’s alibi. Locard found clear evidence that Marie had been strangled. He then scraped underneath Gourbin’s fingernails and examined the results under a microscope. Locard noticed a pink dust among the samples, which he calculated must be ladies’ makeup. In that era, makeup was not mass produced. Locard located a chemist who developed a custom powder for Marie. It matched the fingernail scrapings. Ultimately, Gourbin confessed to the murder. He had tricked his friends into believing his alibi by setting the clock in the game room ahead. But he couldn’t trick Locard. When he strangled his girlfriend, he took some of her—skin cells with traces of makeup—with him.

Pretty convincing, right? Most likely, we can all think of “modern day” cases that were solved as a result of Locard’s Exchange Principle. What’s your favorite example?

So, trust me. No matter how hard you try or how well-intentioned you may be, wherever you go you’ll never just leave footprints and you’ll always take away more than just memories. Mystery writers depend on it. 

MEMORIES OF REMEMBRANCE DAY by Michael Rigg

A few years ago, I made several business trips to London and other parts of the United Kingdom. One trip to London occurred in November, right after a very historic U.S. Presidential election (if I remember correctly) and as the U.K. began to commemorate what the nation refers to as Remembrance Day. My visit that November was brief, but I’ve though often about what I saw and the emotions I experienced.

Beginning with the guns of August in 1914 and finally ending at the eleventh hour of the eleventh day of the eleventh month in 1918, the First World War—the Great War—exacted a horrific toll on human life—more than any previous conflict. The carnage was so vast, involving soldiers and civilians from so many different nations, that historians cannot agree on exactly how many people lost their lives.

 A study conducted on behalf of the Carnegie Endowment estimated that more than 9.7 million military personnel from more than two dozen nations lost their lives. Adding to the tragedy, more than 6.8 million civilians died from war-related maladies such as starvation and disease. In all, about 16.5 million people perished during the “War to End All Wars.”

Great Britain and Ireland, with a combined population of 46.1 million, mobilized 6.1 million army and navy personnel. More than 750,000 military and 600,000 civilians—a total of 1.35 million—died.

After the conflict ended, the United States designated November 11^th, the day hostilities ceased in World War I, as Armistice Day. Later that special observance morphed into a more general celebration of those who have served in uniform—Veterans Day.

In Great Britain, November 11^th is referred to as Remembrance Day. And the Sunday nearest November 11^th is referred to as Remembrance Sunday. Originally a response to World War I, Remembrance Day and Remembrance Sunday now honor those who have fallen in battle in the defense of their nation—similar to Memorial Day in the U.S. Red paper poppies serve as a visual—and visceral—symbol of “remembrance” to the British.

Along with the cost in human life, the First World War decimated the landscape of Western Europe, which had seen bloody back-and-forth offensives and the murderous stalemate of trench warfare. Yet a singular sight gave one man hope. John McCrae, a military doctor from Canada, viewed the battlegrounds and penned a poem, In Flanders Fields:

In Flanders fields the poppies blow

Between the crosses, row on row,

That mark our place; and in the sky

The larks, still bravely singing, fly

Scarce heard amid the guns below.

 

We are the Dead. Short days ago

We lived, felt dawn, saw sunset glow,

Loved and were loved, and now we lie,

In Flanders fields.

 

Take up our quarrel with the foe:

To you from failing hands we throw

The torch; be yours to hold it high.

If ye break faith with us who die

We shall not sleep, though poppies grow

In Flanders fields.

Based largely on the imagery of McCrae’s poem, efforts by various individuals resulted in the red poppy becoming an iconic emblem of Remembrance Day.

Remembrance Day and Remembrance Sunday bring with them parades, speeches, and sermons. But what was most remarkable to me were the rows and rows of red poppies attached to crosses, Stars of David, and other artifacts that were then placed in church yards and parks throughout the city. I remember the fields of honor at Westminster Abby the most. Many of the poppy-adorned artifacts contained pictures or other tributes to the fallen and were viewed in thoughtful, silent reverence by thousands. 

The photograph above gives a hint of the emotional impact of visiting this solemn place, where, to paraphrase, the poppies still blow “. . . Between the crosses, row on row.”