Shades of CSI! Did you know that plant pollen is slowly becoming a basic tool in crime investigation? Like fingerprints and DNA before it, pollen grains and other spores are helping to solve cases of murder, forgery, distribution of illegal drugs, hit-and-run crime, terrorism and much more.
Pollen, it appears, is everywhere. And it tends to cling to skin, clothing, vehicles and tools. It’s even very hard to wash off completely. There are more than 380,000 different plant species currently found all over the world, each with its own unique pollen type. Plus, there is also fossilized pollen of many more species that can be found in soil clinging to a tire or a pant leg.
A forensic palynologist (person who studies pollen) can determine where just about anything has been by studying not just the species of plant the pollen grains found come from, but their composition. For example, near a boreal forest, there would be proportionally more conifer pollen than deciduous tree or grass pollen, but in a grassland, grass and forb pollen would dominate. From there, studying proportions of specific pollen grains can often pinpoint the exact spot.
And adding exotic species, found only in specific gardens, to the pollen mix can clinch the case. (Suggestion: if you’re going to commit a crime, don’t do so in a botanical garden. Its pollen composition will be so unique it will immediately tell investigators exactly where the crime occurred!)
In the Beginning…
The first recorded case of forensic palynology dates back to Austria in 1959. A man had disappeared while vacationing in Vienna and was presumed murdered. There was a suspect, but the police were unable to place him anywhere near that city and he denied having gone there. But they did have the suspect’s muddy boots. They called in geologist Wilhelm Kraus for a soil investigation and he found in the mud various types of pollen including fossil hickory pollen dating back 20 million years and found in only one limited area in Austria, just outside of Vienna. Confronted with proof he’d indeed been near that city, the murder confessed and led the police to the spot where the body was buried … in exactly the area Klaus had predicted.
In some areas, pollen found in illegal drugs is routinely analyzed to determine where the drugs came from … and to see if they can be traced back to a known shipment.
And what about illegal honey? (Bet you didn’t know that honey laundering was a common crime, did you?) Cheap, low-quality imported Chinese honey, often laced with antibiotics, has often been substituted for the real deal. And some companies have been adulterating honey by adding sugar or corn syrup, also illegal. Let forensic palynologists take a look and they’ll soon find the truth! Honey is made from flowers and is loaded with pollen. A quick test will tell the real from the fake and exactly where the honey comes from.
In her book The Nature of Life and Death: Every Body Leaves a Trace, British forensic botanist Patricia Wiltshire recounts her first case, when a criminal gang dumped a body many, many miles from the original crime site. Police found the body quickly enough, picked up the criminals and even impounded their van, but were having a hard time proving the final detail: that the van had been indeed anywhere near the dumping spot. But the gang members had carried pollen grains and fungus spores into the van on their shoes. Wiltshire found a mix of pollen that was specific to the spot where the body was found. Crime solved! But the story doesn’t end there.
Invited to visit the site after the fact, she got out of her car. The police investigators wanted to take her to the exact spot where the body had been found, but she declined. “Let me just test myself,” she said, “And see if I can tell you.” She wandered around the site, noting a ditch with various weed species and a hedgerow with trees and shrubs in diverse combinations. But the mix just wasn’t right … until it was. “I think this is the place!” she said, pointing to a specific section of the ditch, astounding the investigators, because she had found exactly the spot where the body was found!
So, criminals, beware! Never commit a crime when there are plants around!
What? There are plants everywhere?
Then might I suggest it’s probably not wise to commit the crime at all!