Forensic entomology and society

Murder and foul play have always been a part of the human experience. Since the first incorporation of the use of arthropods to solve crimes centuries ago, this forensic tool has captured the human imagination.

Pre-19th century

In 1235 A.D. a death investigator named Sung Tz’u published a book entitled The Washing Away of Wrongs, which described a case where microscopic evidence was used to solve a crime. The investigator requested that all villagers lay their sickles on the ground next to each other. Shortly after, flies began flocking to a single sickle because of trace blood remnants that were still on the weapon from the murder. The owner of the sickle, when faced with this evidence, confessed to his crime. This book was immensely popular and represented the first time that the general public became aware that insects could be use to solve crime.

In 1668, Italian physician Francesco Redi disproved the theory of "spontaneous generation", or abiogenesis. The accepted theory of Redi's day claimed that maggots developed spontaneously from rotting meat. In his experiment, he used samples of rotting meat that were either exposed to the air fully, partially, or not at all. Redi showed that the rotting meat that was fully and partially exposed to the air developed fly maggots, whereas the meat that was completely protected did not develop maggots. His discovery completely changed the way people viewed the decomposition of organisms and prompted further investigation into insect life cycles and into entomology in general.

Popular scientific and fictional literature in the 19th and early 20th centuries

Early twentieth-century popular scientific literature began to pique a broader interest in entomology. The very popular ten-volume book series, Alfred Brehem’s Thierleben (Life of Animals, 1876-1879) expounded on many zoological topics, including arthropods. The accessible writing style of French entomologist Jean-Henri Fabre was also instrumental in the popularization of forensic entomology. His collection of writings Souvenirs Entomologique, written during the last half of the 19th century, is especially useful because of the meticulous attention to detail to the observed insects’ behaviors and life cycles.

The real impetus behind the modern cultural fascination with solving crime using entomological evidence can be traced back to the works Faune de Tombeaux (Fauna of the Tomb, 1887) and Les Faunes des Cadavres (Fauna of the Cadaver, 1894) by French veterinarian and entomologist Jean Pierre Mégnin. These works made the concept of the process of insect ecological succession on a corpse understandable and interesting to an ordinary reader in a way that no other previous scientific work had done. It was after the publication of Mégnin’s work that the studies of forensic science and entomology became an established part of Western popular culture, which in turn inspired other scientists to continue and expand upon his research.

Use of forensic science, including forensic entomology, became a popular part of fiction beginning with the stories of Edgar Allan Poe. He is noted for including graphic depictions of human decomposition in some of his works, including entomological references. The poem The Conqueror Worm, published in 1843, features death symbolized through a 'worm' feasting upon human remains. The worm is a reference to the maggots which are present on a corpse after death and aid in decomposition. In his short story The Premature Burial, published in 1850, he discusses the Victorian Era’s fascination with being buried alive, including references to autopsy procedures of the day and the known pattern of human decomposition. Poe is also recognized as the inventor of the modern detective story. The Murders in the Rue Morgue, published in 1841, follows detective C. Auguste Dupin as he attempts to solve the murder of two women. Dupin carefully assesses the crime scene, noting such forensically important evidence as location and conditions of the bodies, as well as physical evidence present at the scene. Although no specific entomological reference is present, the process of crime scene evaluation is similar to that which a forensic entomologist would undergo using a Death Scene Form. Poe’s character Dupin was the inspiration for countless other analytical crime-solvers, including Sir Arthur Conan Doyle’s detective Sherlock Holmes.

In film

Silence of the Lambs

In the movie The Silence of the Lambs, a series of murders are committed in which the killer skins his victims, leading the investigators to dub the unidentified killer "Buffalo Bill." In a scene depicting an autopsy of one of the victims, the investigators notice something in the victim's throat. The pupa of a Death's-head Hawkmoth is removed with forceps. In another scene, entomologists in the film explain to investigators that the particular species discovered on the victim, identified as Acherontia styx, is not native to the United States and must have been imported by the killer. Because of the enormous popularity of the film The Silence of the Lambs, these scenes referencing the overlap between entomology and forensic science are what most people associate with the work of forensic entomologists.

My Girl

In the 1991 movie My Girl, protagonist Thomas Jay suffers a tragic death due to anaphylaxis after being stung by bees, to which he was mortally allergic. Oftentimes with such cases death due to anaphylaxis, an immediate cause of death may not be apparent, requiring the expertise of a forensic entomologist.

Famous cases

Despite its rich history, forensic entomology has for years remained a branch of forensics lurking the shadows. A handful of well publicized criminal cases helped bring forensic entomology into the limelight and popularized forensic entomology in the modern era.

Paul Bernardo

In 1992, the Canadian press went into a frenzy concerning “The Ken and Barbie Murders.” In June 1991, Paul Bernardo and Karla Homolka tortured, raped, and killed fourteen year-old Leslie Mahaffy. The brutal assaults of Mahaffy were recorded on tape by the couple and helped convict them at trial.

Ten months later in April of 1992, Bernardo and Homolka again raped, tortured, and killed another teenage victim, Kristen French over a period of several days, all captured on video tape.

Once captured and put on trial, forensic entomology began to play an important role. In Paul Bernardo’s trial, renowned forensic entomologist Dr. Neal Haskell helped establish a timeline for one of the victim’s murders. Haskell utilized his understanding of insect development cycles to narrow a fifteen day time interval to a period of four days for the victim’s time of death.

Being one of Canada’s most publicized criminal cases, Dr. Haskell and his testimony brought forensic entomology into many homes.

David Westerfield

In the United States, forensic entomology became known in wider circles through the trial of David Westerfield in 2002 for the abduction and murder of seven-year-old Danielle Van Dam. In this San Diego case, the courtroom became a battle over conflicting reports from four forensic entomologists, Dr. Robert D. Hall, Dr. David Faulkner, Dr. M. Lee Goff, and Dr. Neal Haskell. Dr. Haskell, Dr. Hall, and Dr. Faulker argued that forensic entomology established a time interval that the body of Danielle Van Dam was dumped, which proved to be after Westerfield was already under police surveillance, while Dr. Goff insisted that the victim's body was colonized by larvae earlier than the other three entomologists estimated.

Other cases of importance

A case that shaped Canadian judical history and brought forensic entomology into the headlines was the exoneration of Steven Truscott forty-eight years after being indicted for murder. Forensic entomology also played a role in the investigation of the 1993 raid on David Koresh and the Branch Davidians. Due to the publicity given to these cases, forensic entomology was able to seep further into popular culture.

In 2004 the first (and poorly executed) use of forensic entomology in Brazil demonstrated its importance and potential if done properly. Twenty-six corpses were found in an indigenous region of Rondonia, Brazil. The men were coal miners who came in contact with a group of natives and were brutally clubbed and speared. After the bodies were found they were transported to be autopsied. Arrowheads, spears and clothing were collected but no larvae, pupae or casings were recovered from the crime scene. Once the cadavers were autopsied only fifty-seven larvae were present on the bodies and unfortunately a maximum post-mortem interval could not be established. In part because of the humidity and high temperature environment, the bodies decayed quickly. Since only P. fulvinota was found on the bodies, a species which colonizes all stages of decay, no timeline of succession could be established. Had more thorough work been done on the part of the investigators, a more conclusive post mortem interval could have been established if the casings of stage-specific arthropods had been found .

The CSI effect

From the contributions of movies and TV shows, forensic interest has increased and multiple branches spur into various fields. Entomology, an important area of research for the agriculture and veterinary sciences, also aids in crime scene investigation and forensic chronology. Coined after the explosively popular CBS series CSI, the CSI effect encompasses the overwhelming impact investigative scientific documentary shows.

Some notable American institutions such as Michigan State University and Texas A&M University have recently dedicated entire degree paths geared towards training skilled and knowledgeable forensic entomologists. West Virginia University’s largest major is Forensic Science with over 400 undergraduates.

From 2000 to 2008 there has been a significant increase in the amount of attention paid by the public to forensic entomology as a science. With more attention given to arthropod development, accurate hypotheses can be formed. By following life cycles and tracking seasonal changes entomologists are able to establish the location and weather conditions of an area, which are both particularly useful to homicide detectives. However, with global climate change and increasing temperatures the formulas used to calculate post-mortem intervals may become skewed. Forensic entomologists like Gail Anderson, of Simon Fraser University in British Columbia, Canada, can rely on these formulas to provide certainty in their predictions. It is possible for them to estimate time of death to the exact day even if the person has been dead for a matter of weeks.

The lines blur when pseudoscience dramatized for viewers feeds misinformation and a false sense of security. Problems with jurors arise when they feel unsatisfied. The jury, wanting more conclusive evidence, scrutinizes minute details always expecting some kind of forensic "smoking gun". After watching a season of House, M.D. or CSI, the jurors sometimes feel qualified to make expert decisions. Additionally the TV prejudices could leave some jurors wanting a dramatic experience, which can delay progress.

Even before the trial, the CSI effect can train criminals how to remove evidence and how to stage plausible scenarios. Conversely, victims can intentionally leave crucial traces behind. In one case, a victim who knew she was going to be transported, allowed insects to bite her in hopes of being found and traced back to her area.