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in Sex-Related Death Investigations
The recovery and collection of evidence in sex-related homicide and death investigations is of paramount importance to the overall investigation. Although the general principles of collection, chain of custody and preservation remain the same, there are unique aspects to the types of evidence encountered in sex-related events.
Sex-related homicides frequently result in various kinds of personal evidence including body fluids such as semen, sperm, blood and saliva, as well as hairs, fibers and other microscopic evidence that may be lost or contaminated due to any number of variables.
General types of evidence include Physical, Testimonial, Documentary and Behavioral. Each of these general types of evidence becomes crucial in the identification, apprehension and subsequent prosecution of offenders. However, the investigator should appreciate the nature of physical evidence.
Physical evidence is any tangible article, small or large, that tends to prove or disprove a point in question. It may be used to reconstruct the crime, identify the participants, confirm or discredit an alibi.
The proper collection and disposition of physical or trace evidence from the crime scene and the body of the deceased is of the utmost importance to the investigation and eventual court presentation. The evidence must have been obtained legally for it to be admissible. Therefore, it is imperative for the legal authority to not only collect the evidence, but to consider the proper collection techniques prior to the actual collection of the evidence.
Classifications of Physical Evidence
Class evidence cannot be forensically identified with a specific source to the exclusion of all others. Examples are: the non-DNA analysis of blood, soil, semen, glass, saliva, wood, hair, plant materials, fibers and animal materials.
Individualistic evidence can be positively and forensically identified with a specific source to the exclusion of all other sources. Examples are the DNA analysis of body fluids and hair, latent prints, fracture matches, bite marks and specific handwriting. Transient evidence is temporary in nature, and includes odors, temperature, imprints and indentations in soft or changing materials: butter, wet sand, snow or mud, or markings
Pattern evidence is produced by contact. This includes blood splatter, glass fracture patterns, fire burn patterns, furniture position patterns, projectile trajectory, tire marks, clothing or article patterns, powder residue patterns. Conditional evidence is...