The detective arrives at the crime scene. She photographs the blood spatter, swabs for DNA, lifts latent prints from the windowsill. She notes the position of the body, the entry point, the ligature marks. Then she walks across the moss and keeps going.
She has, in all likelihood, just stepped over the best witness in the room.
That is the central argument of a landmark review published in the journal Forensic Sciences Research — a paper that surveyed 150 years of scientific literature to ask how often a common, unremarkable group of plants has contributed to solving crimes. The answer, assembled by a team of researchers from the Field Museum in Chicago, Michigan State University, George Washington University, the New York Botanical Garden, and institutions across three continents, was both unexpected and damning: moss and its botanical relatives have cracked cases dating back nearly a century. And they are almost entirely absent from modern forensic training and practice.
What Moss Is — and Why That Matters Forensically
Moss belongs to a plant group called bryophytes, which includes mosses, liverworts, and hornworts. They are among the most ancient plants on Earth — colonizers of bare rock, inhabiting the edges of what other organisms cannot tolerate. They have no vascular system, no roots in the conventional sense, and no flowers. They absorb water and nutrients directly from whatever surface they contact: rain, soil, air, the substrate they grow on.
These characteristics make them forensically distinctive in ways that most investigators have never been trained to recognize.
Because bryophytes obtain their chemistry directly from their immediate microenvironment, their species composition at any given location reflects the precise conditions of that spot — the soil pH, the moisture level, the light regime, the presence of specific organic compounds. A patch of moss on a north-facing embankment in a Michigan wetland will be a different assemblage from a patch on a cemetery headstone in suburban Chicago, and both will differ from what grows in the shaded damp of a Finnish forest floor. This locality specificity means that moss fragments recovered from a suspect’s shoe, clothing, or vehicle can be matched — with high precision — to a reference sample taken from a specific crime scene location.
There is more. Fragments and shoots of moss are easily detached or broken off and can become attached to items such as shoes, clothing, or vehicles, and can exist in samples of soil, dirt, or other debris. A fragment can be as small as an eyelash. It survives transport, drying, compression. It persists on fabric and in crevices of footwear long after a suspect has left the scene and believes themselves clean. And only a small quantity of material is needed to narrow a sample down to its primary group — a degree of identification that can place a person at a location, or eliminate them from it.
Perhaps most powerfully for cold case work: moss is a clock. Its growth rates are well-documented, and in the right conditions, bryophyte growth on a skeleton, a grave marker, or disinterred remains can be used to estimate the postmortem interval — how long a person has been dead, or how long remains have occupied a particular location — with a precision that soil chemistry and entomological evidence alone cannot always achieve.
A Century of Cases: What the Literature Reveals
Matt von Konrat, head of botanical collections at the Field Museum in Chicago, led the research team that combed through a century and a half of scientific literature looking for documented instances of bryophytes contributing to criminal investigations. What he and his collaborators found was simultaneously encouraging and sobering.
Across a century-and-a-half of scientific literature, the study’s authors identified only 11 confirmed instances of moss samples helping to explain unsolved deaths. The earliest case dates to 1929. Across the entire arc of modern forensic science, one of the planet’s most ubiquitous plant groups has been formally deployed in criminal investigation fewer times than the average detective works in a single year.
But those cases are instructive precisely because they demonstrate what is possible.
Finland, 2001: Linking Suspect to Scene
In a Finnish homicide investigation, bryophyte fragments were recovered from a suspect and analyzed against reference samples collected from the scene where human remains were discovered. The analysis provided a geographical link between the individual and the location — placing them at the site in a way that other physical evidence had not conclusively established. The case is documented in the reviewed literature as one of the cleaner examples of moss serving its most direct forensic function: association evidence.
Michigan, 2011: Narrowing a Search from Seven Counties to 50 Square Feet
The most extensively documented American case in the study involves the 2011 abduction and homicide of Katherine “Baby Kate” Phillips, a four-month-old infant in Mason County, Michigan. Her father, Sean Phillips, initially denied knowing what had happened to his daughter. When investigators examined dried mud recovered from the soles of his shoes, they found Sphagnum moss — a genus with highly specific habitat requirements — combined with a collection of other plant species that do not typically grow in proximity to one another.
What they found led them to Lemke Drain in a wetlands area in northwestern Mason County, a location Phillips later pointed to on a map. Though the exact location of the body has not yet been found, the botanical analysis narrowed the original search area from seven counties to 50 square feet — a zone that combined the same composition of diatoms, mosses, sedges and trees found on his shoes.
Phillips is currently serving 19 to 45 years for second-degree murder. The baby’s remains have never been recovered — possibly, researchers note, because a four-month-old infant’s bones may not have been sufficiently mineralized to survive more than a decade in a wetland environment. But the moss on his shoes told investigators where to look, and a map drawn by the killer confirmed it.
Alsip, Illinois: Moss Contradicts a Suspect’s Timeline
In a case that did not involve a murder but demonstrated moss’s potential for establishing temporal forensic evidence, authorities in Alsip, Illinois, investigated cemetery workers suspected of disinterring human remains and reselling burial plots. Experts from the Field Museum were brought in to examine moss found with the disinterred remains.
The Field Museum experts used mosses found with disinterred remains to determine how long they had been buried. Their findings contradicted the suspect’s timeline and placed the accused at the scene of the crime, providing crucial evidence that led to the successful conviction of guilty individuals.
The mechanism here was growth rate analysis: the moss had colonized the remains at a measurable pace, and the extent of that colonization was inconsistent with the timeline the suspects offered. The plant had, in effect, kept a more accurate record than the humans involved.
International Cases: Portugal, Taiwan, Austria, Sweden, Italy
The study documents moss applications beyond American borders. In Portugal, bryophyte analysis helped determine whether skeletal remains belonged to a person who had been missing for six years — a case where the plant’s growth provided temporal anchoring that linked the remains to a specific disappearance. In Taiwan, moss evidence contributed to differentiating between a suicide and a homicide, a distinction with profound legal consequences. In Austria, Sweden, and Italy, postmortem interval calculations using moss growth assisted in establishing when victims had died.
The Forensic Method: How Moss Evidence Is Collected and Analyzed
The practical process of using bryophytes as forensic evidence involves several distinct methodological steps, each of which requires trained botanical expertise that most crime scene units do not currently possess.
Recovery. Moss fragments must be identified and collected before they are destroyed by conventional crime scene processing. On footwear, this typically involves careful examination of the sole with magnification; on clothing, fibers may need to be separated under stereomicroscope conditions. Soil samples from vehicles, tools, or personal items may contain bryophyte material invisible to the naked eye.
Identification. Species-level identification of bryophytes requires specialist botanical knowledge. Many moss species are morphologically similar at the fragment level, and accurate identification depends on microscopic examination of cellular structure, leaf arrangement, and reproductive features. This is not a skill that generalist forensic scientists possess — it requires forensic botanists or bryologist consultants.
Reference sampling. The evidentiary value of moss evidence depends on comparison: unknown samples recovered from a suspect must be measured against known reference samples from the crime scene location. Mosses can be incredibly helpful in establishing connections between unknown samples that are found and known reference samples collected at a specific location, the crime scene. The quality of this comparison depends on the thoroughness of reference collection — ideally across multiple microhabitat zones at the crime scene.
Postmortem interval analysis. For cases involving skeletal remains or burial sites, the relationship between moss growth and elapsed time must be calibrated against local growth rate data for the species present. This calibration is site-specific and requires documentation of local environmental conditions.
DNA analysis. An emerging dimension of moss forensics involves molecular identification — using DNA extracted from bryophyte samples to achieve species-level and even population-level identification when morphological analysis is inconclusive. This technique is not yet standard in forensic practice but has been demonstrated in research settings and represents the likely direction of the field.
Why Investigators Are Missing It
The study’s authors are direct about the gap between what moss forensics can offer and how rarely it is used. Von Konrat said investigators are “simply overlooking it because they don’t know what they’re looking at.” That diagnosis points to a structural failure in forensic training rather than a failure of individual investigators.
Modern crime scene training curricula in the United States and most of Europe are built around a core of physical and biological evidence types: DNA, fingerprints, ballistics, blood pattern analysis, digital evidence. Botanical evidence of any kind — let alone bryophyte-specific analysis — is rarely included. The result is a systematic blind spot. Investigators do not collect what they do not know to look for. Evidence is not preserved when it is not recognized as evidence.
The problem is compounded by the fact that forensic botany sits at the intersection of two professional communities — botanists and law enforcement — that have historically operated in near-complete separation. Academic botanists with the expertise to conduct forensic bryophyte analysis are not embedded in crime labs. Detectives and scene-of-crime officers have no pathway to consult one. The expert network that would make moss evidence routine simply does not exist in most jurisdictions.
There is also a chain-of-custody challenge specific to biological evidence: botanical samples degrade under conditions of improper storage, are susceptible to contamination from other plant material during transport, and require specialist handling protocols that are not described in standard evidence preservation guidelines.
Criminal Psychology and the Evidentiary Blind Spot
From an investigative standpoint, the underuse of forensic botany has an unintended consequence that goes beyond missed evidence: it creates a class of physical transfer that perpetrators currently have no reason to manage. Experienced offenders know to avoid leaving fingerprints, to dispose of items that carry DNA, to vary their routes to minimize surveillance capture. But very few know that the dried mud on their shoe soles, or the fragment of plant material caught in a bootlace, could be mapped to a specific 50-square-foot wetland in rural Michigan.
This knowledge asymmetry is itself forensically valuable — for now. If forensic botany enters mainstream investigative practice, that advantage will diminish as awareness of the technique spreads. The Baby Kate case is instructive: Phillips did not clean his shoes with any particular care because he had no reason to believe the botanical composition of dried mud could be forensically significant. He was wrong, and it led investigators to the location his daughter’s remains likely occupy.
Global Context: Forensic Botany’s Emerging Profile
Forensic botany — the application of plant science to legal investigation — has a longer history than its current low profile suggests. The field formally dates to the early twentieth century and has periodically surfaced in high-profile cases: pollen analysis helped convict Bruno Hauptmann in the Lindbergh kidnapping case in 1935, based on wood identification of the ladder used in the crime. Palynology — the study of pollen and spores — has been used in murder cases in New Zealand, the UK, and Scandinavia to place suspects at specific outdoor locations.
What is new in the current study is its specific focus on bryophytes, its systematic review of the evidentiary record, and its explicit call for institutional change: more training, better collection protocols, wider expert networks, and formal integration of botanical evidence into crime scene standard operating procedures.
The research team behind the paper includes specialists from institutions across multiple countries and disciplines — a deliberate construction intended to demonstrate that the expertise required for this kind of analysis already exists, scattered across universities and herbaria and natural history museums, waiting to be mobilized.
What the Field Requires Next
For forensic moss analysis to become a standard investigative tool rather than an occasional academic intervention, several structural changes are needed. Forensic training programs at the academy and undergraduate levels would need to incorporate basic botanical recognition — enough for a scene-of-crime officer to identify moss-bearing material and preserve it appropriately. Reference herbarium collections would need to be systematically georeferenced in ways that support forensic comparison. Expert consultation pathways would need to be formalized so that investigators know how to access a bryologist when they need one.
The cost of these changes, in material terms, is modest. Moss does not require expensive laboratory infrastructure. It does not need a centrifuge or a mass spectrometer. It needs someone who knows what they are looking at, a reference collection, and a microscope. The barrier is not resources. It is awareness.
The Moss Grows On
The oldest forensic moss case in the literature is from 1929. For nearly a century, the evidence has been accumulating in quiet, unhurried patches on woodland floors and cemetery headstones and the soles of shoes walked through Michigan wetlands, growing at its own pace, recording what happened and when, waiting for investigators who know to collect it.
Plants, and specifically bryophytes, represent an overlooked yet powerful source of forensic evidence that can help investigators link people, places, and events. That formulation, offered by study co-author Jenna Merkel, is precise and restrained in the way that good science is restrained. What it means in practice is this: somewhere, right now, there is a crime scene where moss is growing on something relevant. Nobody is collecting it. Nobody has been trained to see it.
The field is not waiting for a new technology. It is waiting for investigators to look down.
ForensicTimes · forensictimes.com · Investigative Journalism on Crime, Justice & Forensic Science © 2026 ForensicTimes. All rights reserved. Published May 1, 2026.
