Download
1 / 37
370 likes | 416 Vues
INTRODUCTION. Chapter 1. What exactly is Forensic Science?. Forensic science applies the knowledge and technology of science to define and enforce laws. The History of Forensics. Mathieu Orfila (Spain) “Father of Forensic Science”(1787-1853)
E N D
INTRODUCTION Chapter 1
What exactly is Forensic Science? Forensic science applies the knowledge and technology of science to define and enforce laws.
The History of Forensics • Mathieu Orfila (Spain) “Father of Forensic Science”(1787-1853) • Established the science of Forensic Toxicology, by studying the effects of toxins on animals • Alphonse Bertillon (France) (1853-1914) • Developed the science of Anthropometry – a way of taking extensive body measurements to identify people. This technique of personal identification was considered extremely accurate for 2 decades and was eventually replaced by fingerprinting.
The first criminal identification card filedby the New York State Bertillon Bureau. The NY State Bertillon Bureau in 1902
More important people! • Francis Galton (1822-1911) • Proved the uniqueness of human fingerprints and published a book called “Finger Prints”. Current fingerprinting techniques are based on his research. • Leone Lattes (1887-1954) • Devised a technique to determine the blood group of a dried bloodstain and applied the technique to criminal investigations. (The ABO blood groups were discovered by a Dr. Karl Landsteiner in 1901)
Dr. Karl Landsteiner in his laboratory, working on blood samples
And more… • Calvin Goddard (1891-1955) • Used microscopy to determine if a bullet was fired from a particular gun, and if that compares to the suspect’s weapon and a crime scene bullet. Modern firearms examiners still use his techniques. • Albert S. Osborne (1858-1946) • Published a book “Questioned Documents”, and was responsible for the acceptance of documents as scientific evidence by courts. Modern document examiners still use his book as primary refernce.
A couple more… • Walter C. McCrone (1916-2002) • Did extensive work with microscopy to examine forensic evidence. • Hans Gross (1847-1915) • The first person to write about marrying all arms of science (Botany, antropology, chemistry, physics, mineralogy, etc.) into one unified investigative science: Forensics.
Last but not least… • Edmond Locard (1877-1966) • Established “Locard’s Exchange Principle” which state that, whenever 2 objects come in contact with each other, there will be an exchange of materials between the two. Therefore, when a criminal comes in contact with an object or a person, a cross-transfer of evidence occurs. So you can find something of the criminal on the victim and vice versa.
In 1932, thanks to J. Edgar Hoover, the director of the FBI, launched a national lab that would offer forensic services to the entire country’s law enforcement agencies. • Today, the FBI laboratory is the largest and most reputable in the world.
Basic Services of a Full-Service Crime Lab • Physical Science Unit • Biology Unit • Firearms Unit • Document Examination • Photography Unit
Optional Services of a Full-Service Crime Lab • Toxicology Unit • Latent Fingerprint Unit • Polygraph Unit • Voiceprint Analysis Unit • Evidence-Collection Unit
Specialized Forensic Services These are provided by specialized individuals, and are not usually a part of a full-service crime lab. • Forensic Pathology • Forensic Anthropology • Forensic Entomology • Forensic Psychiatry • Forensic Odontology • Forensic Engineering
1.Forensic Pathology Investigates sudden, unnatural, unexplained, or violent deaths. Questions a forensic pathologist must attempt to answer: - Who is the victim? - What injuries are present? - When did the injuries occur? - What caused the injuries? - What was the time of death? http://www.pathguy.com/TimeDead.htm If a cause of death cannot be determined by external observation of the body, then an Autopsy is required.
Autopsy (means to see for oneself) This a medical dissection of a body to determine cause of death. Causes of death can be classified as: - Suicide - Homicide - Accident - Natural causes - Undetermined
Autopsy cont’d. • The early stages of decomposition after death involve: • Rigor mortis: the muscles first relax, then stiffen. The body becomes rigid. Rigor mortis occurs within 24 hours after death and terminates within 36 hours. • Livor mortis: Once the heart stops pumping, the blood tends to pool in the parts of the body closest to the ground due to gravity. The skin in these areas appear purplish. However, skin that was restricted by belts, etc. will not appear purplish. This can help determine if the body was moved after death. Livor mortis begins immediately after death and continues for up to 12 hours.
Rigor Mortis Livor Mortis
Autopsy cont’d. • Algor mortis: this is the conditions where the body temperature cools and reaches the ambient or room temperature. The location, size of body, clothing, weather conditions, etc. all play a role in algor mortis. Generally speaking, beginning an hour after death, the body loses heat at the rate of 1 or 1.5 degrees Fahrenheit per hour until body reaches ambient temperature.
Pallor Mortis Pallor mortis (paleness of death) is a postmortem paleness which happens almost instantaneously (in the 15–120 minutes after the death) because of a lack of capillary circulation throughout the body. Paleness develops so rapidly after death that it has little to no use in determining the time of death.
Other Autopsy Factors • Potassium levels in vitreous humor of eye: after death, cells of the inner eye release potassium into the ocular fluid called vitreous humor. Examining these levels help determine time of death. • Amount of food in stomach: can help determine when last meal was eaten.
2. Forensic Anthropology Deals with identification and examination of human skeletal remains. Bones degrade at an incredibly slow rate. They can tell: - Sex - Age - Race / Origin - Type of injury (cause of death?) Forensic anthropologists are often needed to identify victims of a mass disaster such as air crashes, 9/11 WTC disaster, bombings, etc.
Ways to tell male pelvis from female: spread of ilium: female more flared and cradle-like with anterior iliac spines farther apart vs. more straight “up-and-down” in male shape of hole in ischium: smaller and triangular in female vs. larger and rounded in male angle across pubic symphysis: pubic arch: less than 90° (acute angle) and more sharply angled in male, greater than 90° (obtuse angle) and more rounded in female inner diameter and distance between ischia: larger in female--big enough for head of baby to pass through
Sometimes forensic anthropologists have to use Facial Reconstruction artists to help identify the remains.
http://www.crimelibrary.com/criminal_mind/forensics/art/5.htmlhttp://www.crimelibrary.com/criminal_mind/forensics/art/5.html
3. Forensic Entomology The study of insects and their relationship to a criminal investigation. Can help determine time of death. After death, specific insects become inhabitants of the corpse in a specific sequence. Blowflies are usually the first to arrive. Knowing the life cycles and studying the maggots can help determine time of death. Ambient temperatures can play a role in insect life cycles, so it can be tricky to rely solely on this method.
4. Forensic Psychiatry The relationship between human behavior and legal proceedings is examined. Forensic psychiatry can help determine: - If a person is fit to stand trial - Suspect’s behavioral profile - Behavioral patterns of criminals (Profiling)
5. Forensic Odontology Using teeth to identify remains. Tooth enamel is the hardest substance in the body and usually the last to decompose. So teeth can be used (and old dental records such as X-rays and casts) to identify a body in an unrecognizable condition.
6. Forensic Engineering This aspect of forensic science includes accident reconstruction, causes and origins of fires and explosions.
Body Mystery • http://americasunknownchild.net/Medical.html • www.crimelibrary.com
