Informative description of a crime

If contamination is present in these reference samples, the positive identification of a victim’s body may fail or may result in mixed DNA profiles, which in turn will lead to a confusing identification. It is thus important that kinship analysis be performed to further strengthen the results obtained when using antemortem reference samples. Another way to further strengthen the positive result generated from an antemortem reference sample is to analyze a second direct reference sample such as another family member or a second antemortem reference sample such as a bloodstain card.

These reference samples are generally more reliable than personal items such as toothbrushes and razors. This type of crime scene investigation is usually associated with difficulties in isolating intact DNA due to the exposure of tissues to high temperatures of the fire. However, there have been frequent testing and optimization of DNA isolation protocols that it is now possible to increase the amount of DNA yield even if the tissue source has been burned in a fire or has been kept in preservatives such as formaldehyde for months, years, or more so, decades (as in the case of mummified corpses).

A better approach to DNA isolation will involve the retention of the 0. 5 mM EDTA solution with the pulverized bone in order to prolong chelation of calcium ions and other EDTA-inhibitors as well as the employment of collagenase for enzymatic dissociation of tissues (Schmerer et al. 1999). After such incubation, proteinase K will be introduced, as detailed in the original procedure. In addition to DNA analysis, entomology may also be employed in crime scene investigation.

The presence of insects in specific larval stages may generate information on the time of death of a victim or a group of victims. The information generated from such analysis may be combined with the data generated from DNA analysis to provide a bigger and more informative description of a crime or a disaster. The use of entomological data in forensic analysis may also provide information of the sequence of death of individuals in a crime scene.

For example, if a mother and child were found dead in their home, the presence of insect larva at particular stages of development will provide information on whether the mother or the child died first. The sequence of death may be determined on the victim’s body by checking which larva is at a later stage of development, meaning that this victim died first and the other victim which shows larva at a younger stage of development means that he died later.

The weather, in relation to the presence of the larva, will also provide clues to the time of death of a victim. It is scientifically known that during winter, the insects take a longer time to migrate and produce larva, hence if a body is found during the winter, death must have ensued earlier because the larva presence in a body must that it must have taken some time for the insects to find this body and nest on it.

The analytical power of crime scene investigation in combination with forensic analysis provides another powerful and reliable tool in the investigation of crimes and disasters (Alonso et al. , 2005). However, it is important that precautionary measures be taken in order to prevent any false positive identification which is turn influence convictions of suspects as well as wrongful sentencing to either life imprisonment or death.

References

Alonso A, Martin P, Albarran C, Garcia P, de Simon L, Iturralde MJ, Fernandez-Rodriguez A, Atienza I, Capilla J, Garcia-Hirschfeld J, Martinez P, Vallejo G, Garcia O, Garcia E, Real P, Alvarez D, Leon A and Sancho M (2005):  Challenges of DNA profiling in mass disaster investigations. Croat. Med. J. 46(4):540-548. Budimlija ZM, Prinz MK, Zelson-Mundorff A, Wiersema J, Bartelink E and MacKinnon G (2003):  World Trade Center human identification project: Experiences with individual body identification cases. Croat. Med. J. 44:259-63.