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…
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
...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.
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.
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...
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
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).
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...
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.
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...
John L McIntosh. (2003) . Handbook of Death and Dying. Volume 1: The Presence of Death. Thousand Oaks, CA: Sage Reference.
The concept of brain death is not something that can be easily determined at just a glance. It is an intricate course of tests and time to determine if the process of brain function is evident. An important series of questions to ask yourself is, “what constitutes brain death,” “how is it defined, “and “what happens afterwards?” Brain death is not to be confused with a coma because they are entirely different. Organ donation is the most common outcome of someone who is diagnosed brain dead. If this occurs first hand to you or your family member, would you go out of your way to determine if the doctors were correct? This essay will explain the tests that are performed on the body that is thought to be brain dead, the difference between brain death and a coma, and how families could possibly handle the results of a person being determined brain dead.
...I do think that rigor mortis is very reliable in determining the time of death, although not an exact indicator. It is somewhat accurate in determining time of death and placement of body when the person died, although it should not be the only factor in the case. The results are just an approximation so it will not give the exact hour the person died, especially since there are so many other things that can effect the process of rigor mortis. It is helpful when someone has just died or within a few days, although if the person has been dead for weeks or more, investigating the persons state of rigor mortis is not useful. I learned in my research that hundreds of forensic science tools are needed in each investigation and can take years to put a crime scene puzzle together. Studying a bodies process of rigor mortis and lividity are the best first steps in doing so.
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.
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...