The Sequence of Events Assisted by Computer Graphics: Two Case Studies

Every complex industrial accident needs to be treated with the very same methodological approach that is normally used by the investigators when they have to reconstruct a crime, for example, a violent case of homicide. It is common knowledge even to non-experts that every crime scene is a mine of possible information which, when it is carefully interpreted, gives precious aid to the investigator in the difficult task of reconstructing the “dynamics” of the crime. If, for example, the investigator starts out by examining the particular shape of the wounds on the victim’s body, he or she could come up with some idea of the type of weapon that inflicted the death blow. At the same time, from a study of the prints left on the floor by the murderer’s shoes, a number of hypotheses could be made about his or her build or physique. For these very reasons the investigators carry out measurements, trying to “freeze” the relative positions of the surrounding objects and the body of the victim, gathering organic traces and taking fingerprints. Using techniques that are totally in accordance with Anglo-Saxon countries, for example, it is possible to set out from the examination of traces of blood on surface elements to formulate hypotheses about the position of the source that was bleeding and sometimes also the way in which the death blow or blows were inflicted, how much force was used and whether the act is potentially ascribable to a single individual of a certain physique or sex. And so it could go on. Any investigator making an inquiry into the reconstruction of the dynamics of a crime starts off, therefore, from a detailed interpretation of the traces present on the scene. The investigator gathers as much of these as possible is the first preparatory step towards the success of the subsequent phase, which consists in formulating the hypotheses of reconstruction concerning the dynamics of the accident. A critical analysis of the hypotheses the investigator can formulate shall be linked with the interpretation of the traces. This is a crucial phase of the inquiry because it forces the investigator to move forwards by carrying out a rigorous screening of those hypotheses that seem in any way implausible as they are not effectively capable of explaining the presence of all the traces that have previously been identified and catalogued. Here we are dealing with the need to eliminate the hypotheses of reconstruction that have turned out to be inconsistent with the traces. This verification phase is often conducted by questioning any possible suspects, by using an “empirical verification” to reconstruct the sequence of movements that have hypothetically been made based on the traces present on the crime scene or also, in some cases, using virtual techniques to reconstruct the scene of the accident and the relative movements of the body.