Rigor Mortis: This term refers to the rigidity of the muscles of the dead person. It is no accident that a common term for a dead person is “stiff”. Your muscles hold their tone and are able to contract and release through a complex chemical reaction of two molecules in the muscle cells: actin and myosin. Two chemicals, acetyl triphosphate and acetyl diphosphate allow this to happen. When a person dies the body is in a particular position. Left in that position for a period of time, the body will reach full rigor or stiffness. This happens because the two chemicals ATP and ADP are not going through their normal cycle. So rigor starts right away, it strengthens throughout the body and reaches full rigor in about six to eight hours. The rigor will leave the body in about twenty-four hours. Evaluating this helps provide a range for the time of death. Sooting: It is important to determine how far the muzzle of the gun was to the victim’s body at the time the weapon was discharged. The term sooting describes deposits of gunpowder residue on the skin of the victim. This burnt gunpowder can be washed or wiped off the body. Because it has little mass and would best be described as smoke residue, it can’t travel far from the barrel of the gun, so sooting is an indication of a close gunshot wound. Gunshot wounds are always described within a range. I define close range from near contact with the skin as approximately six to eight inches away from the target. Stippling: This is another term that relates to distance of the gun from the victim at the time of discharge. Stippling is partially burnt gunpowder residue. It has greater mass than the smoky, massless sooting residue and therefore can travel farther than soot. Once this unspent powder hits the victim’s skin it causes little red dots as it burns the epidermis, called “tattooing.” Booth sooting and tattooing can occur in a close rage shooting. If only stippling exists, then the gun was farther away. In my experience stippling occurs when the gun is eight inches to a little better than twelve inches away from target. All of these ranges depend upon the weapon and the ammunition used. Ranges can be reproduced with similar guns and ammunition to those in the incident by calibrating the distance from a whiteboard and then firing at multiple ranges. Victimology: A victimology is one of the keystones to deriving meaning from the evidence of an investigation. After the evidence is collected, documented and processed, the effort to give meaning to what all the evidence tells us is called “evidence reconstruction.” Evidence reconstruction begins with first studying the victim. This process is called building a victimology. The entire life is of importance, especially the last 48 hours before to death. In the first episode it readily became obvious that the victim knew the killer. There was passion involved in the assault. The victim was in the midst of trying to change her life as evidence of textbooks around the scene. A victimology must give meaning to why the victim was a victim. DNA Profile: Your DNA defines who you are uniquely. Most of your DNA is just like everybody else's but there are areas in the double helix that identify you more accurately than fingerprints. There is DNA in the nucleus of the cell, representing the profile of both the mother and father of the sample, and there is DNA from the engines of the cells, the mitochondria, representing only the maternal side of the sample. Each cell has many mitochondria, but only one nucleus. In most cases, mitochondrial DNA testing is done because a smaller sample is sufficient enough for identification.
1 Comment
Miles Alexander
8/22/2016 10:55:15 pm
Fascinating. Enjoy your program and learn quite a bit from you. If you care to answer two questions that I'm sure you get asked all the time, kindly indulge a fan.
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