After death, rigor mortis is first visible in the body’s smaller muscles, including those in the face and upper body. It takes some time for it to show up in larger muscles. So the fact that the victim is showing rigor mortis only in the face and upper body indicates that she has not been dead for very long – about two hours (Claridge, 2016). It was noted that lividity is also visible in the posterior region of the victim but is not fixed. This fits the two-hour timeline, as lividity begins within the first hour of death and does not become fixed until after six hours. To further estimate the PMI, we can measure body temperature. The equation typically used for this is 37.5˚C – 1.5˚C. In other words, the victim’s body temperature drops 1.5˚C every hour after death until it reaches the ambient temperature of the surrounding environment. Converting Fahrenheit to Celsius, the victim’s body temperature in this case would …show more content…
have been 30.3˚C at the time it was taken. This is a difference of 7.2˚C. In doing the math, this means that the victim died 4.8 hours (or a little less than 5 hours) prior to the recording of this temperature. This means death occurred just under four hours prior to when the body was discovered. Petechial hemorrhaging, or tiny red dots in the whites of the eyes, occurs when the capillaries in the eyes rupture. This typically happens when a person breathes against resistance or tries to breathe against resistance. This is a sign of terminal asphyxia and may be caused by smothering, strangulation, hanging, or anything else that obstructs an individual’s airways or compresses the neck. At its most basic, it is immediately clear that this victim was asphyxiated somehow. Upon further investigation, a fractured hyoid bone and deep bruising of the strap muscles of the neck were discovered. This could only have occurred through a great amount of force being applied to the neck and is further indication of terminal asphyxia. Considering the position of the bruising, it is most likely that these injuries are a sign that the victim was killed by manual strangulation. In addition, extensive vaginal tearing with bleeding is indicative of forceful sexual interaction. Absence of sperm does not mean a sexual assault did not happen, only that the assailant did not ejaculate inside the victim. This likely means that the attacker used a condom to prevent leaving behind traces of his biological fluid during the assault. Regardless, based on the information at the scene, it is very likely that the victim was forcibly raped and, in trying to break free of her attacker, was strangled to death to stop her from screaming to attract attention and struggling against him. A crusty yellow stain was found on the bed sheet and tested with several presumptive tests to determine the likelihood that it is blood, semen, or some other form of bodily fluid. A Tetramethylbenzidine (TMB) test showed a blue-green color within one to two seconds. Although prone to false positives, this kind of reaction is indicative of blood being present within the stain. A Kastle-Meyer (KM) test turned to a pink color within one to two seconds. This test reacts with hemoglobin in blood to produce such a reaction. Although not a common test anymore, an alkaline phosphatase (AP) test came back positive. This test measures the amount of the mentioned enzyme that is present within white blood cells (Leukocyte alkaline phosphatase, n.d.). So in other words, this test also indicates that there is blood present within the stain. The protocols for the laboratory do not call for the microscopical identification of sperm.
However, due to the fact that semen stains yellow, there is reason to believe that this stain consists of seminal fluid mixed with blood, possibly from the bleeding that occurred in the victim’s vaginal cavity. Further laboratory tests should be done to identify whether this is the case including a prostate specific antigen (PSA) test, and further definitive tests should also take place to confirm the presumptive tests for the presence of blood in the stain. Polymerase chain reactions (PCR) are used to “repeatedly duplicate or amplify a strand of DNA millions of times” (Saferstein, 2014). The short tandem repeat (STR) analysis consists of three to seven repeating base pairs of short sequence elements that replicate along a molecule of DNA. In this case, there are only seven variants with five to eleven repeats. Running this DNA information through CODIS would allow for law enforcement to find matches to these variants to further identify the
contributors. Assuming we do not have access to CODIS, or CODIS failed to provide a sufficient DNA match, we have to determine the probability that the recovered DNA matches the suspect and/or victim. To do this, we need to remember that the estimated population frequency for having nine matching STRs is approximately one out of 850 million people (Saferstein, 2014). In this case, CSF1PO matches the suspect’s sperm exactly. Epithelial cells from the victim’s vaginal cavity match with 10 and 11, while the suspect matches with 11 and 12. In laymen’s terms, the swab taken from her vaginal area contains DNA matching both her and the suspect. TPO numbers show the 8 and 11 STRs from the suspect and the 10 and 11 from the victim, while the epithelial swab shows 8, 9, and 11. This again shows foreign DNA present that came from the suspect. Likewise, the TH01 numbers match both the suspect (6 and 7) and victim (9 and 9.3) and contain DNA from both (6, 7, 9, and 9.3). Both the victim and the suspect have contributed DNA to the fractions tested. The odds of these numbers matching different individuals is very small – around one in 283 million. At trial, the suspect testified that he had consensual sex with the victim. Based on the presence of vaginal tearing, this claim is not plausible. In addition, the presence of bruising on her neck, evidence of strangulation, and death by asphyxiation all heavily points towards rape. If the victim “liked it rough,” so to speak, there would have been indications of older bruising and scarring. In this case, there was none. Therefore, it is strongly indicative of nonconsensual sex. Likewise, the suspect’s claim that the victim was alive and well when he left the motel room is not plausible. The autopsy showed petechial hemorrhaging in the victim’s eyes and face, which occurs when a person’s ability to breathe is cut off and leads to suffocation. As previously mentioned, these hemorrhages only show up when an individual is trying to breathe against resistance. The internal examination also indicated the fractured bone in the larynx and deep bruising on her neck’s strap muscles. Strangulation through heavy force for a fair period of time is required for this to have happened. Also, while it is not clarified in the scenario, we are assuming that we have access to the security footage at the motel. If no one else shows up on camera in the half hour after the time the suspect left the room – and presumably the maid did not find anyone else in the room besides the victim – this completely rules out the possibility that anyone else entered the room during the supposed window of opportunity for someone else to attack the woman. No one else being present means no one else could have killed the victim. Due to the violent nature of the death, there is no plausible way that he could not have known that she was dead when he left. Based on the evidence, this is likely how the crime happened: The victim was in the room with her attacker, whether by free will or not, and was forced onto the bed and raped. During the attack, the assailant choked her with his hands. In the process, he broke a bone in her neck and cut off her air supply, effectively suffocating her to death. He most likely used a condom with the intention of preventing any evidence of his presence at the scene, but semen still leaked onto the bed. The stain contained DNA evidence proving that he was there and was the one who had forceful intercourse with the victim. The assumed semen stain with his DNA signature is mixed with blood from the victim, further solidifying the case against him. There is virtually no chance that these DNA signatures belonged to anybody else, proving that the suspect is the one who raped the victim and left her for dead.
The COmbined DNA Index System (CODIS) is a computer software program that is operated and maintained by the Federal Bureau of Investigations, which allows law enforcement agencies to search and exchange DNA information. It was originally created in 1990 as a pilot software project that would allow 14 State and Local laboratories to communicate and share biological evidence data to aid in criminal case closure. Following the DNA Identification Act of 1994, the FBI established the National DNA Index System (NDIS) that currently serves over 25 countries in their own DNA Data banking initiatives (Federal Bureau of Investigations, 2010). NDIS, populated by many State DNA Index Systems (SDIS) and local DNA Index Systems (LDIS) provide a mechanism for cross checking previously disparate legal and judicial entities for serial criminal offenders (USA.gov, 2010).
Using PCR and Gel Electrophoresis to Determine Genotype. In certain situations, it is necessary to identify DNA retrieved from a sample. When there is a small sample in need of identification, Polymerase Chain Reactions are used to multiply the DNA. in the sample in many identical samples.
Deoxyribonucleic acid (DNA) is an acclaimed extraordinary discovery that has contributed great benefits in several fields throughout the world. DNA evidence is accounted for in the majority of cases presented in the criminal justice system. It is known as our very own unique genetic fingerprint; “a chromosome molecule which carries genetic coding unique to each person with the only exception of identical twins (that is why it is also called 'DNA fingerprinting ')” (Duhaime, n.d.). DNA is found in the nuclei of cells of nearly all living things.
PCR or polymerase chain reaction is not a DNA typing technique, but a variety of different DNA tests (Riley). PCR duplicates and increases the quantity of a DNA strand which is beneficial to forensic scientists who are faced with little quantity of materials (Saferstein 394). The introduction of PCR-based testing in DNA analysis required scientists to switch to smaller targets that had the same repetitive variation (Jones). This is how short tandem repeat, the newest method of DNA typing,
When a person is battling between life and death physicians have to check for signs of death. Kastebaum states that “the most common signs of death have been lack of respiration, pulse, and heartbeat, as well as failure to respond to stimuli such as light, movement, and pain. Lower body temperature and
Familial DNA searching works by using the combined DNA index system (CODIS) to compare DNA samples taken from crime scenes to DNA profiles already recorded in the local, state, or national criminal DNA database. There are many indexes in the database; two of the largest are the offender index, a catalogue of DNA profiles from previously convicted felons, and the forensic index, a catalogue of DNA from crime-scenes. A DNA sample is run through the database by CODIS’ matching algorithm that searches the indexes against one another to generate matches according to how often base pairs, or “markers,” repeat in th...
John L McIntosh. (2003) . Handbook of Death and Dying. Volume 1: The Presence of Death. Thousand Oaks, CA: Sage Reference.
Edwards, William D., Wesley J. Gabel, and Floyd E. Hosmer. "On The Physical Death of Jesus Christ". JAMA-Journal of the American Medical Association. Mar. 21, 1986, v256
...cap of the sperm pink and the nucleus red, and a picroindigocarmine dye, which turns the mid piece of the sperm blue and the tail of the sperm green. The stained samples would then be placed under a microscope and hopefully spermatozoa would be present so that DNA testing could be performed.
The criteria or definition of brain death was re-examined in 1968 by a committee at Harvard Medical School and is part of the criteria used today. They defined it as when a patient; is unresponsive to stimulus; cannot move or breathe without the aid of a ventilator and has no brain stem reflexes. Several tests are done in order to determine if a patient meets these criteria and this can be done by physicians and neurologists. A brain dead patient is legally dead and a death cer...
There are thirteen standard tandem repeats used in modern forensics, and together these sequences create a DNA profile. Except in the case of identical twins, the probability that two people have the same genetic code at all thirteen core loci is less than one in one trillion (Jones, 2004). Investigators compare these...
Patient one, a man attempted to commit suicide, by electrocuting himself because of depression. After the incident, he told his psychiatrist, that his brain was dead, but his body was living. That he no longer needed to eat or sleep. However he acknowledged that his mind was alive, but could not understand if his brain was dead how his mind could be alive. Still though he kept insisting his brain was dead. Psyc...
Rigor mortis is the stiffening of the muscles that happens 2-3 hours after a human or animal dies, beginning in the head and then it working its way down to the toes. After 12-18 hours, the body becomes completely stiff and the only way to move any of the joints is to force them, most likely breaking them. After 2 days, rigor mortis begins to wear off, once again starting in the head and then downward towards the toes. Once this process is finished, the body begins to decay, and eventually starts to decompose. Rigor mortis is very crucial in the criminal justice system and is used to provide clues and evidence in finding out information about someones death.
After decades of tests, documentation, and research, some scientists believe that consciousness can prevail even after the body has died. A near-death experience (NDE) is an unusual experience that takes place on the brink of death (Greyson, 2000) and usually involves an out-of-body experience or a vision of a tunnel of light. Although it can be difficult to prove that a near-death experience has occurred, there are tests that provide undeniable evidence that an NDE has taken place. An unbelievable 3% of the world’s population has had an NDE (Choi, 2011). That is an incredibly high percentage when considering that 7 billion people inhabit the Earth. A lot of those people have recounted their experiences and provided absolute proof that their experience took place. These reports have only strengthened the argument that NDEs actually happen and supports the most significant question about NDE research: Can consciousness survive bodily death? Science has proven most phenomena that occurs in everyday life, and has also, for centuries, concluded that nothing occurs after one dies, when in fact, consciousness can prevail, even after the body has experienced conventional death. This can be proven by research conducted to determine what a near-death-experience is, documentation on these experiences by their experiencers, and tests to verify that these experiences have actually taken place.
It has been found that the decomposition process is best divided into five stages: fresh stage, bloated stage, decay stage, post-decay stage, and remains. The fresh stage starts the moment the individual died and lasts until bloating can be observed. The bloated stage is usually within two to seven days after death. Putrefaction begins at this stage and the gases produced from bacteria cause...