Sometimes individuals get confused as to why investigators go in one direction or another at the beginning of an investigation. Inductive reasoning is generally used in the beginning of an investigation because given the data at the scene we first check on the most probable hypothesis as to what happened and who may be the suspect. For example: data shows that most serial killers are Caucasian males. So if the police have multiple suspects in a serial killing, they may look at the male Caucasian suspects first. The important point in using inductive reasoning is that one must remember to clearly distinguish between what is a probability and what is a fact.
These are most commonly seen in suicide or torture cases. The tool is most often a sharp object like a knife. They are superficial cuts to the skin, never intending to cause death but rather pain. Where the hesitation marks are can tell you much about whether they were self-inflicted or done for torture or control.
Knife Wound Analysis:
A good medical legal investigator has to know not only the anatomy of the body but also the anatomy of a knife. Most knives have a sharp edge and then on the opposite side a flat, non cutting edge called a spine. This is a single edged knife. Some knives are actually “daggers” and have sharp edges on both sides. Some knives have a “quillion” or “hilt” just before the handle of the knife. Each part of a knife’s anatomy can tell us the angle of attack, the length of the blade, the design of the blade or the shape of the hilt. Having a working knowledge of knives and understanding pattern wounds on the body can tell you much about the knife and the perpetrator.