Bugs, Thugs and the Law Insects as tools in legal investigations

Transcription

1 Bugs, Thugs and the Law Insects as tools in legal investigations Dr. David Rivers Department of Biology Loyola University Maryland

2 My teaching Hired to teach: 1) Invertebrate Zoology 2) Comparative Physiology 3) General Genetics 4) Intro Anatomy and Physiology 5) General Entomology Other courses taught Forensic Entomology Forensic Biology Organismal Biology Process of Science Exploring Ecosystems Insects in Our World Seasonal Adaptations of Animals Research in Biology Honors Research

3 Forensic Science All things forensic are on the rise, especially in terms of interest by college students Television shows like CSI, NCIS, Law and Order and others have had a major impact, good and bad. The CSI effect The science is now being mandated to actually be science, if to be used in US judicial system Forensic Entomology has been a beneficiary of all the attention

4 Forensic Entomology What is it? Brief: The broad field were arthropod science and the judicial system interact. In depth: The branch of forensic science in which information about insects is used to draw conclusions when investigating legal cases relating to both humans and wildlife, although on occasion the term may be expanded to include other arthropods.

5 Plan of Attack Forensic Entomology What is it really? Medicocriminal Entomology What most people think of Application of Insects to Criminal Investigations Bugs, Thugs, and the Law

6 Forensic Entomology What is it really?

7 Forensic Entomology Three recognized sub-fields: 1) Medico-criminal: Focuses on the criminal component of the legal system that deals with necrophagous or carrion insects that infest and feed on human remains and carrion 2) Urban: Deals with insects affecting man and immediate environment. 3) Stored Product: Focused on insects found in foodstuffs.

8 Urban Entomology Insects in human habitation Includes those that are synanthropic and some rural species Stored Product Entomology Insects in food and food products Defect action levels must be exceeded -both are subfields of General Entomology as well as Forensic Entomology

9 Medicocriminal Entomology What most people think of

10 Medico-criminal Entomology This is what most people think of when hearing term Forensic Entomology Why? Bugs on bodies are what is shown on crime shows, Dirty Jobs, and in news articles It is gross in a fascinating way Solving murders with maggots captures the imagination

11 Medico-criminal Entomology What can insects reveal about a crime, especially a suspicious death or homicide? Two important pieces of information: 1) Estimation of the post mortem interval based on development. 2) Whether the body has been moved to its present location.

12 Characteristics of useful insects as physical evidence necrophagous on humans or other animal remains feed on necrophagous species development tied to corpse/carrion developmental details under wide range of conditions are known are poikilothermic

13 Necrophagous Diptera The most important ecological evidence at a crime scene

14 Why flies? Larvae of most species from the families Calliphoridae and Sarcophagidae are entirely saprophagous/necrophagous Flies and corpse are poikilothermic Timing of colonization and succession relatively predictable. Blow flies are generally first colonizers Most need protein to lay eggs, although some do not need to eat before laying eggs or larvae Display determinant growth

15 Calliphora vomitoria Family Calliphoridae Sarcophaga bullata Family Sarcophagidae Chrysomya rufifacies Family Calliphoridae Musca domestica Family Muscidae

16 Important Forensic Flies Calliphoridae: blow flies and bottle flies Sarcophagidae: flesh flies Muscidae: house fly, face fly, dump fly Fanniidae: lesser house fly Phoridae: scuttle fly, coffin fly Piophilidae: skipper flies Scathophagidae: dung flies Stratiomyidae: soldier flies Psychodidae: moth and sand flies

17 Why not beetles? Necrophagous Coleoptera are generally the second most important insects on carrion in terms of Forensic Entomology Their utility is limited because: 1) Neither adults or larvae are exclusively necrophagous 2) Development of many species is indeterminant 3) Are more variable in terms of timing of succession

18 Necrophilia americana Siliphidae Creophilus maxillosus Staphylinidae Oiceoptoma noveboracens Siliphidae Dermestes maculatus Dermestidae

19 Application of Insects to Criminal Investigations Bugs, Thugs, and the Law

20 The Crimes 1)Suspicious deaths and homicides: estimations of PMI and location of body 1)Abuse and neglect: myiasis 1)Pet abuse and neglect 1)Wildlife poaching 1)Toxicology: analysis of larvae and puparia 1)Blood spatter analysis: insect artifacts 1)Terrorism: use as weapons and as tools

21 Insects and Death

22 Insects and Death Necrophagous fly larvae are most useful Oldest larvae on corpse is collected Some are preserved as physical evidence Others are reared to adult for identification Developmental duration is estimated based on degreeday models, developmental threshold, and experimental data This developmental estimate is used to estimate the minimum post mortem interval

23 Factors Influencing Development on Corpse Ambient temperature Maggot mass temperature Tissue composition and size Conspecific and allospecific competition Clothing or other materials covering body Sun vs. shade Seasonality Concealment in artificial or natural location Cause and manner of death

24 Casey Anthony Murder Trial Case hinged on entomological evidence, mainly the scuttle fly Megaselia scalaris

25 Entomotoxicology Concerned with detection of drugs or toxins in necrophagous insects from corpse Also on impact of exogenous chemicals on development of forensic indicator species Includes detection of gunshot residues and other explosive materials Fly larvae from early colonizing species are most useful Those feeding on surface tissues are best for GSR detection

26 Blood Spatter Fly Artifacts

27 Fly Artifacts Insects are not helping with criminal investigation Spots or artifacts contaminate bloodstain evidence and confuse what is real versus what is not Artifacts originate from regurgitate and liquid frass (feces)

28 Fly spots Blood spatter

29 Entomological Terrorism The idea of using insects as weapons is not new However, today s more sophisticated use does rely on new technologies and opportunities Threats to US are in three forms: 1) Direct attack by biting and stinging insects 2) Use of insects as vectors of disease 3) Targeting agriculture

30 Forensic topics allow discussions of: Succession Competition Predation and parasitism Environmental influences and adaptation Growth and development Introduction of modeling and statistics, especially with degree-day concepts and post mortem interval calculations Small insect collections but that require a lot of information

31 Additional Information: Byrd, J.H. and J.L. Castner Forensic Entomology: The Utility of Arthropods in Legal Investigations. CRC Press, Boca Raton, FL. Rivers, D.B. and G.A. Dahlem The Science of Forensic Entomology. Wiley-Blackwell Publishers, West Sussex, U.K.

32 Career Paths to Forensics Forensic Studies Minimally a college degree is required, usually graduate training is needed Majors: Psychology, Sociology, Criminology/Criminal Justice Employers: Law enforcement, government, academia Forensic Science Minimally a college degree is required, at least a master s degree Majors: Biology, Chemistry, Computer Science, Physics, Mathematics Employers: Crime labs, government and private industry, academia Majors in red are high demand for employers with those underline being priority areas by the FBI, NSA, and Homeland Security

33 Career resources American Academy of Forensic Sciences: Loyola University s Forensic Studies:

34 Questions?