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Just Science: 2019 NIJ R&D: Just Flies and Their Artifacts

NCJ Number
David Rivers
Date Published
July 2019
3 pages

This ninth episode of the 2019 R&D season of the NIJ-funded Just Science podcast series consists of an interview with Dr. David Rivers, a professor at Loyola University, who has conducted research on insect stains and the development of a quantifiable confirmatory test for fly contamination of bloodstain evidence.


Background information provided for the interview indicates that there are approximately 86,000 species of flies that have been identified throughout the world. Of these, approximately 16,000 species have been identified in the United States, Approximately 1,000 of these species are known to be attracted to decomposing bodies. For post-mortem interval estimates, the species that lay eggs or deposit larvae are often considered the most useful in determining time of death. Dr. Rivers, however, has focused on another characteristic of their behavior, i.e., the various artifacts produced as a direct result of a fly's behavior. In this interview, he discusses the complexity of insect behavior and its potential benefits in a forensic investigation. The particular research in which he is currently involved is focusing on the various artifacts that particular fly species deposit when they feed on a substance that may be relevant to a crime scene. Among the fly artifacts discussed in this interview are substances dispensed by flies in the course of feeding on particular crime-related substances, such as blood and dead bodies. The focus of the interview is on products dispensed by flies in the course of digesting the substance on which they are feeding, such as elimination artifacts and regurgitant artifacts, along with their potential relevance to criminal investigations.