Bugs as Silent Witnesses: The Role of Insects in Crime-Solving

The unlikeliest of detectives are crawling under our very feet. As it turns out, insects play no small role in solving crimes. 

While many people are familiar with DNA analysis, fingerprinting, and ballistics as key components of forensic investigations, another fascinating field that plays a significant role in crime-solving is forensic entomology.  This branch of science is the study of insects and the deceased, offering valuable insights into the timeline and circumstances surrounding a person’s death. 

Forensic entomologists deal with various cases, from murders and homicides to accidental deaths and suicides. They may be called in to help identify the cause of death when the victim’s body is in an advanced state of decomposition. 

The profession of forensic entomology is often misunderstood, with many people imagining it as a field where scientists study bugs for the sake of science. However, forensic entomologists work closely with law enforcement agencies and lawyers, using their knowledge of insects to assist in legal cases. They are often called upon to determine the time of death of a victim by studying the insects found on or near the body. This information can be crucial in solving crimes and bringing perpetrators to justice.

A Brief History of Entomological Forensics

The roots of entomological forensics can be traced back to ancient times when the observation of insects on decomposing bodies was recognized as a means of gathering information about crimes. The Chinese in the 13th century and the Romans in the 2nd century BCE were known to take note of fly activity around corpses. However, it wasn’t until the late 19th and early 20th centuries that the field of forensic entomology began to take shape.

One of the pioneering figures in entomological forensics was Jean Pierre Mégnin, a French scientist who conducted extensive research on the insect species associated with human decomposition. His groundbreaking work in the late 19th century laid the foundation for future advancements in the field. Mégnin’s studies led to establishing key principles, such as the predictable succession of insects on a corpse and using insect evidence to estimate the postmortem interval.

In 1855, Dr. Bergeret d’Arbois conducted a pioneering criminal investigation in Paris, France, which involved the use of forensic entomology. The discovery of a baby’s body hidden behind a fireplace mantle in a house prompted Dr. d’Arbois to examine the insect infestation on the remains. Through careful analysis, Dr. d’Arbois determined that the baby had been deceased for several years. This revelation shifted the focus of guilt from the current occupants of the house to the previous ones.

Since then, the field has continued to evolve with advancements in scientific techniques and technology. Today, forensic entomology is widely recognized as a specialized branch of forensic science, and entomological evidence is routinely used to provide valuable insights into crime scenes, aiding law enforcement agencies and legal professionals in their quest for truth and justice. 

The Processes and Techniques of Forensic Entomology

Crime Scene Collection and Assessment

Forensic entomologists carefully collect and examine insect evidence found at crime scenes. They pay attention to details like temperature, humidity, and sunlight, as these affect insect behavior. They observe and document the types of insects and their life stages found near the body. Special tools like small containers and tweezers are used to collect and preserve the insects for further analysis.

Insect Identification and Preservation

In the laboratory, entomologists use microscopes and reference materials to identify the collected insects based on their physical features. By studying their shape, color, and other characteristics, they can determine the species of insects found at the crime scene. Properly preserving the specimens ensures their integrity for future analysis and potential use as evidence in court.

Estimating the Time Since Death

Forensic entomologists estimate how long it has been since a person died by studying the insects found on or near the dead body. They consider factors like the types of insects present, the temperature, and the weather conditions. By understanding the life cycle and growth rates of these insects, they can make an educated guess about when the person passed away.

Examining Insects for DNA

Sometimes, entomologists can extract DNA from insects found at crime scenes. This DNA can be used to identify people involved in the crime. For example, if an insect contains blood from a suspect, the DNA in that blood can be compared to the suspect’s DNA to see if they were at the scene.

By following these methods and techniques, forensic entomologists can uncover important information about a crime. Their work helps investigators understand the role insects play in forensic investigations and contributes to solving mysteries.

Blowflies: The First Crime Scene Visitors

One of the most important groups of insects studied by forensic entomologists is blow flies, which are often the first insects to colonize a decomposing body. These flies are beneficial in estimating the time since death, as their development and behavior are well understood. Blow flies lay eggs on a decomposing body, and their larvae (maggots) feed on the decaying tissue. By studying the age and development of the larvae, forensic entomologists can estimate the time since the eggs were laid, which in turn can provide an estimate of the time of death.

Fascinated? Watch entomologists study how bugs affect the decomposition of human remains in this video from National Geographic (viewer discretion is advised).


From Beetles to Bees – Other Important Insects in Forensic Entomology

In addition to blowflies, other insects play crucial roles in crime investigations. Beetles, such as dermestid and carrion beetles, provide insights into later stages of decomposition, while certain wasp species indicate burial or concealment of remains. Ants can help determine the duration of decomposition, and mites offer valuable information in cases involving long-term decomposition or buried remains. By studying the characteristics, behavior, and life cycles of these insects, forensic entomologists contribute to understanding the timing, location, and circumstances of a crime, enhancing the accuracy of criminal investigations.

Crimes Where Insects Were Crucial Evidence

Likely the most well-known murder in the forensic entomology world is the Buxton murders. In September 1935, Dr. Buck Ruxton committed a heinous crime by murdering his wife Isabella and their housemaid Mary Rogerson. To conceal the evidence, Ruxton traveled about 100 miles from his home and disposed of their bodies in a remote area in the Scottish Borders. However, the discovery of the bodies prompted a thorough investigation, and one crucial piece of forensic evidence came from the insects found on the corpses. 

By analyzing the larvae of bluebottle flies, specifically Calliphora vicina, investigators determined that the larvae were between 12 and 14 days old, providing a crucial timeframe for when the bodies were disposed of. This evidence played a significant role in leading the police to Ruxton and ultimately securing a successful prosecution. Today, the maggots from the Ruxton murders remain preserved as part of a special collection, serving as a testament to their contribution in solving this notorious crime.

Bugs are continuing to play a bigger role in solving crime, as you can read in this breakdown of 10 heinous crimes that were solved with forensic entomology. 

Challenges and Limitations of Forensic Entomology

When analyzing insect evidence, forensic entomologists encounter variables and uncertainties that can introduce reasonable doubt into their findings. Factors such as temperature, humidity, and environmental conditions significantly influence insect development rates, making it difficult to accurately determine the time of death. These variations can create ambiguity and make it challenging to establish a precise timeline for the crime.

 Additionally, the presence of multiple insect species with different life cycles adds complexity to the analysis, potentially leading to conflicting interpretations. These challenges highlight the need for caution and expertise in drawing conclusions from insect evidence. Understanding and addressing these limitations can help investigators navigate the intricacies of forensic entomology and make more informed decisions in solving crimes.

Technological Advances and Improved Methodologies

Technological advances have led to new opportunities in forensic entomology in recent years. For example, DNA analysis can now be used to identify the species of insects found at a crime scene and to match insects found on a victim’s body to insects found in a suspect’s home. In addition, new methods of chemical analysis can be used to detect the presence of drugs or other substances in insect samples, providing significant evidence in cases involving drug trafficking or food contamination.

Final Thoughts on The Future of Insect-Assisted Crime Solving

Insects, once considered mere pests, have become silent witnesses to the darkest secrets of crimes. Through the expertise of forensic entomologists, their presence and behavior are decoded, illuminating the path to truth and justice. With each case solved, the significance of forensic entomology grows, reinforcing its position as a remarkable and indispensable tool in the arsenal of crime-solving.

Dino Sys
Author: Dino Sys

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