Crime scene reconstruction relies on a team effort to analyze physical evidence using deductive and inductive reasoning to form theories about what occurred. The team must avoid biases and continually re-evaluate evidence. Physical evidence provides definite conclusions through deductive reasoning, while circumstantial evidence provides possible leads. Testimonial evidence requires corroboration. Re-enactments can show if theories fit evidence. Reconstruction only includes evidence with a confirmed chain of custody. Each piece of evidence is analyzed separately before linking evidence to form plausible reconstruction theories.
Objectivity is the professional detachment practiced by individuals to avoid letting personal beliefs or biases affect the conclusions reached through observations. Expectations or biases can have a negative effect on the process of reconstruction by leading to incorrect analysis or interpretation of the information provided by the evidence. For this reason, all data and evidence is continually re-evaluated several individuals analyze the evidence and present independent interpretations.
Deductive reasoning is used when a given fact or finding leads to a definite conclusion. Inductive reasoning is used when a given fact or finding leads to a conclusion that is probable but not definitive. In this case, there are also other probable conclusions. The falsifiability of a theory is used when an investigators tests the theory to determine if it can been proven false by the physical evidence.
Generalizing about aspects of evidence can be both helpful and harmful to an investigation. False linkage occurs when an investigator assumes a link between two or more objects of evidence. The information available to make crime scene reconstruction theories is often much less than needed to create a full timeline of events. Reconstruction relies on information from toxicology tests, autopsies, interrogations, and many other sources which may not be available for days, weeks, months, or sometimes years after the incident.
Reconstruction is a team effort that involves putting together many different pieces of a puzzle. The team as a whole works to answer the typical “who, what, where, when, and how” of a crime scene. Attempting to answer the “why” question by contemplating a perpetrator's inner motivations may bias the investigator’s observations. Crime scene reconstruction relies on the combined efforts and expertise of medical examiners, criminalists, and experts in specialized fields.
The physical evidence left behind at a crime scene plays a crucial role in reconstructing the events that took place surrounding the crime. Although the evidence alone does not describe everything that happened, it can support or contradict accounts given by witnesses and/or suspects. Information obtained from physical evidence can also generate leads and confirm the reconstruction of a crime to a jury. The collection and documentation of physical evidence is the foundation of a reconstruction.
Direct physical evidence from a crime scene provides a definite conclusion or direction through the use of deductive reasoning to state a fact that can be understood by everyone. Circumstantial evidence from a crime scene provides a lead but no definite conclusion through the use of inductive reasoning to identify many possible causes for the state of the evidence. Testimonial evidence from eye-witness accounts should be carefully scrutinized because it is highly subjective and heavily biased. Therefore, crime scene reconstruction should only include testimonial evidence that is corroborated by aspects of physical evidence.
A re-enactment of events at a crime scene can show if a theory of how an event occurred is physically possible and if physical evidence is consistent with that theory. A re-enactment can be carried out by live personnel, mannequins, or computer-generated models.
Evidence without a confirmed chain of custody cannot and should not be included in reconstruction. A missing link in the chain of custody of an item means it was unaccounted for a period of time during which it could have been tampered with, contaminated, or damaged. If there is any question as to the legality or authenticity of testimonial evidence, it cannot and should not be included in reconstruction.
Different categories or types of crime scene evidence have to be studied with very specific techniques and considerations during the investigation. Each item of evidence should first be analyzed and tested separately from all other evidence without falsely linking items of evidence during the initial phase of the investigation. Once all possible information has been recovered from each item, the information can be coupled with that from other items to observe whether or not separate items of evidence make sense together or verify an event.
The final steps of crime scene reconstruction require the reconstruction team to bring together all the evidence and information to form plausible theories and a plausible sequence of individual events. The right connections have to be made among all the parts involved so as to portray the relationship among the victim, the suspect, and the crime scene. All available information and evidence must fit into the overall picture.
An event timeline will define each event or “moment” that occurred at a crime scene in various probable orders within a known or estimated time frame. The evidence that signifies the start or end of events at a crime scene can give a clue as to the missing events that must fit in the middle. Once the various orders have been identified, each sequence should be tested against the evidence. If successful, reconstruction can play a vital role in aiding a jury to arrive at an appropriate verdict.
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