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Nature’s Lab

Written by Jake Stump
Photographed BY Brian Persinger

Maggots and corpses make for suitable nightmare fodder. But for forensic entomologists like Rachel Mohr, creepy crawlers and cadavers come with a real job — a job to uncover truth. 

Mohr studies insect and arthropod biology as they relate to criminal and civil cases. 

Dead body in the woods? Mohr can nail down the time of death by analyzing the bugs feasting on the flesh. In fact, Mohr, a teaching instructor in the Department of Forensic and Investigative Science, is the only certified forensic entomologist in the mid-Atlantic area of the United States. 

With a keen eye, a touch of science and a backpack of gadgets, Mohr brings to life the answers that can lead to justice. 

Collecting evidence

Teaching instructor Rachel Mohr (left) collects evidence at a mock crime scene with Nicole Mathias, a forensic and investigative science student. Mohr, a certified forensic entomologist, studies the ecological interaction of insects and carrion, or the decaying flesh of the dead.

Tools of the Trade

Take A Picture. It Lasts Longer. 

Mohr calls this the “most important tool in forensic investigations.” She relies on a Nikon D700 to snap photos of insects, the body and the general scene. Photos serve as visual evidence and can help highlight potentially overlooked aspects of an investigation. 

Nikon camera

Half and Half

Here’s the problem with maggots: “They all look the same. They’re little white squirmy worms.” That’s why Mohr kills half of the maggots in a sample while she allows the other half to fully develop into adults. Generally, there are four stages of transformation beginning with the egg, followed by the maggot (or larva), the pupa (pictured below) and the adult insect. By allowing maggots to transform into pupae and then adults, it’s easier to correctly identify the species, Mohr said. 


Trowel on the Prowl

This handy tool scoops up maggots roaming away from the body before they transform into pupa. The hand trowel (or garden spade) can also be used in digging for other insects in outdoor death scenes or for general soil sampling.

Trowel and glove

Weathering the Scene

Environmental thermometers collect temperatures at different heights and locations relative to a body. Probe thermometers measure temperatures in a mass of maggots and even within soil. Weather is a critical key to an investigation, as insects prosper in warmer environments.


Blowfly Life Cycle

The life cycle of a blowfly technically has six parts: the egg, three larval (maggot) stages, the pupa and the adult fly.


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