Last Updated on April 7, 2025
Plants might not be able to talk, but they may be able to say quite a bit when it comes to a criminal investigation. This is all thanks to a science called forensic botany, which may not be widely known, but can be incredibly useful in helping to identify a suspect. But just like all forms of forensic science, it is not a 100% reliable indication of guilt.
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Identifying a Location of a Crime
The first way plants can be used to help solve crimes is to help police recognize a location where something may have happened. In fact, the use of plants to help identify locations related to crimes has been used long before “forensics” was even a widely used term. That’s because suspected killers may have traces of plants on their clothing or shoes that could indicate where they have been. Similarly, if a corpse has a plant on her body or clothing that is not found where the body is discovered, this could provide evidence of where she was before the murder or where the murder actually occurred if the body was moved after the fact.
Historically, this was only helpful if the plants found on the victim or suspect were rare enough to indicate their location. For example, if a suspect had dandelion fluff on the cuff of his pants, that wouldn’t be particularly useful because these weeds grow just about everywhere. On the other hand, if a victim discovered in Vista had a needle from the wollemi pine, he would likely have been at the the Alta Vista Botanical Garden or the San Diego Zoo Safari Park because these are some of only places this rare tree can be found in North County.
Plant DNA Identification
These days, plants may be able to help even more when it comes to investigating a crime. That’s because just like us, they have DNA -and also just like us, that DNA has a habit of going everywhere. In fact, because most plants must shed pollen and seeds in order to reproduce, it’s very easy to end up with some plant DNA on you or your vehicle whenever you walk or drive through a plant-filled area such as a forest, field, garden, or even someone’s yard.
While a piece of dandelion fluff still might not help solve a crime because there are so many dandelions, if a leaf got trapped in the bed of a suspect’s truck, this could be a major crack in the case. Imagine, for example, that police are able to match the DNA from a leaf found in a woman’s truck to the DNA from a tree located outside the place where her husband was murdered.
The Time of an Incident
Interestingly, plants can even help identify not just where, but also when something may have happened. Most plants of a given species tend to rot at a similar rate in similar circumstances. So if police discovered a scrap from a victim’s coat that was covered with dead vines that were ripped out of the ground when he was fighting his attacker, a forensic botanist may be able to use the relative decay of the vines to identify a rough time frame of when the victim died, even if the body has not yet been discovered.
Similarly, the decay of a leaf found in the truck bed of a suspected murderer could indicate what time the person was near the tree that dropped the leaf.
Finding a Missing Person
In fact, researchers at the famous Body Farm have even been investigating the idea that trees may look different when they are exposed to the chemicals released from a rotting body. While yet unproven, the theory says that because bodies release a lot of nutrients, particularly nitrogen, they could change the appearance of foliage in the immediate area, possibly causing the plant’s leaves to change color or reflectance.
If the theory pans out, then investigators may be able to more efficiently and effectively scan forests to find signs of missing persons who have since perished near vegetation.
Remember that Forensic Science Isn’t Everything
Of course, while forensic botany can be an invaluable tool in helping police investigate crimes, it’s also important to keep in mind that it isn’t foolproof. Consider the example above of a leaf being found in the truck bed of a woman whose husband was murdered. While the evidence may indicate that she visited the place her husband died and even a rough time frame, that doesn’t automatically mean she is guilty. If it is a place she drives by all the time, for example, she easily could have driven by around the same time as her husband was killed and have no idea that he was even away from home.
Similarly, someone could have planted the evidence on her vehicle to help frame her.
Or, while less probable, it’s still possible that the leaf was coincidentally blown across the area and ended up landing in her truck bed though she never even visited the area he died. In this case, an expert witness could testify on her behalf stating that the wind patterns at that time went directly from the tree to her home. A forensic botanist may even provide evidence that the leaf suffered damage indicating it was swept up in the air and then was scraped along the sidewalk, which is different than the damage a leaf gets from traveling in the back of a pick up truck.
Watch What You Say When Suspected of a Crime
That being said, when someone is caught in a lie, it can make them seem very guilty, which is why police often try to speak with suspects as soon as possible and without their attorney present. If, for example, the woman in the example above claimed she drove her truck 300 miles away at the time her husband was murdered and wasn’t back for two months until police arrested her, the evidence would indicate she was lying.
This is why attorneys are so adamant that you refuse to speak to the police without a lawyer present. When you are caught in a lie, it makes your defense far more difficult, even if you are entirely innocent of the crime.
If you have been charged with any crime, please call (760) 643-4050 to schedule a free initial consultation with attorney Peter M. Liss.
