Introduction to Forensic Science.ppt. forensic nursing
- 1. INTRODUCTION TO FORENSIC SCIENCE Presented by Dr Varun Modgil Assistant Professor, Deptt of Forensic Medicine, DMCH Ludhiana
- 2. Important Definitions • The term 'forensic' actually comes from the Latin word 'forensis,' which means 'forum' and refers to a public, open court. In other words, forensic science means science that is intended to be used in court • Forensic science can be defined as the application of scientific methods to criminal cases. In particular, forensic science deals with the analysis of evidence in criminal cases
- 3. HISTORY OF FORENSIC SCIENCE • The first-ever autopsy may have been Antistius observing the body of a slain politician named Julius Caesar • By 1773, chemist Carl Wilhelm Scheele developed a chemical test to detect arsenic (evidence of poisoning) in corpses • The first Central Forensic Science Laboratory was established at Calcutta during 1957. To begin with, this laboratory was organized into four basic disciplines viz. Forensic Physics, Forensic Chemistry, Forensic Biology and Forensic Ballistics
- 4. IMPORTANCE OF FORENSIC SCIENCE IN MEDICAL SCIENCE • Cause of Death • Criminal Investigations • Child Abuse and Neglect • Sexual Assault Cases • Accident Investigations • Disaster Victim Identification • Toxicology and Poisoning • Public Health and Epidemiology • Expert Testimony • Exonerating the Innocent
- 5. FORENSIC SCIENCE LABORATORY • FUNCTIONS OF FSL 1. To examine evidence material 2. To help the investigating officer for scientific guidance in crime detection 3. To help the investigation officer to collect evidences by visiting scene of crime 4. To train the investigating officer for use of modern and sophisticated techniques in crime detection
- 6. STRUCTURE OF FSL 1. Toxicology 2. Serology 3. Biological 4. Molecular biology 5. Physical division 6. Ballistic and explosive division 7. Finger printing division 8. Polygraphy division
- 7. STRUCTURE OF FSL 9. Narcoanalysis division 10. Brain fingerprinting 11. Prohibition(Alcohol/narcotics analysis) division 12. Trace evidence division 13. Cyber forensics 14. Documents analysis division 15.Photography Section 16. Forensic acoustic speaker Identification
- 8. PHYSICAL EVIDENCE 1. In case of poisoning/ food poisoning - Chemical analysis of viscera/ body fluids- to know nature of poison. - Chemical analysis of food/ utensils/clothes etc. above are corroborative evidence. 2. In assault & murder - Examination of weapon/ object to detect crime - Blood grouping from blood stains on victim hair in victim's hand, saliva on cigarette butts-identity of assailant - Clothes examination- identification
- 9. PHYSICAL EVIDENCE 3. In burn deaths - Examination of clothes/ skin- for smell of kerosene or petrol - Examination of metallic objects, teeth & bones-for identification of charred body 4. In firearm injuries - Examination of missile - to know the nature and type of firearm- Examination of marking on missile - to know which gun was used in firing 5. In hanging/ strangulation - Matching of ligature
- 10. PHYSICAL EVIDENCE 6. In drowning - Detection of diatoms in body tissues and water 7. In sexual offences - Examination of vaginal fluid, blood/ seminal stains- whether crime committed. - Examination of hair, epithelium, blood grouping- identity of accused- Examination of clothes & site of offence 8. In Vehicular Accidents - Blood grouping - for identification - Tyre marks- to know the vehicle. - Grease, mud, blood, tissues, glass pieces, hair paint etc. on vehicle-which vehicle involved in accident. - Examination of clothes- site, identity of accused
- 11. PHYSICAL EVIDENCE 9. Identification - It is possible from finger prints, foot prints, hair, blood semen, clothes, bones, teeth and tissues 10. Disputed paternity/identity - Cases settled by examination of blood group sand DNA finger printing 11. Burglary - Examination of paint, algae, vegetable matter glass fragments on his tools, clothes or body 12. Forgery - Examination of documents, paper ink, pencil and type writer - Erasures/ alterations/ obliterations- under UV Rays Identification of handwriting
- 12. ANALYTICAL TECHNIQUES Chromatography • It is an important technique to separation, identification and purification of a mixture. • It is based on two different media stationary phase and mobile phase. The speed at which each substance is carried along by the mobile phase depends upon its solubility and its affinity for the sorbent • It is very helpful to detect poisons and chemicals. • Thin layer chromatography Paper chromatography is used for the separation of protein and in studies about protein synthesis. • Gas chromatography is used for alcohol, ester, lipid and amino groups
- 13. ANALYTICAL TECHNIQUES Electrophoresis • It is a technique using separate mixture of ionic solutes by differences in their rate of migration in an applied electric field. • The electrically charged protein components move on the phase plate and at the end, the plate is treated with coloring agent causes appearances of visible characteristic bands specific for a particular protein. Spectroscopy • There are a lot of spectroscopy methods which is based on various effects of interactions between radiation and matter, among which vibrational spectroscopy deserves special attention, these methods are widely used forgathering structural information on biological systems investigations such as this helps identification of the various forms of hemoglobin.
- 14. ANALYTICAL TECHNIQUES Spectrophotometry • Colorimeter, U.V. and I.R spectrophotometry, mass spectrometry, emission spectrophotometry, atomic absorption spectrophotometry these are the various quantitative and qualitative analytical spectrophometer Neutron activation analysis • It is an isotope specific analytical techniques for the qualitative and quantitative measurement of chemical elements • In nuclear reactor, the trace element is irradiated with neutrons which causes radioactive decay and in this process gamma rays are liberated, which are measured and counted and it is adopted for measuring trace metals in biological samples
- 15. ANALYTICAL TECHNIQUES Microscope • Comparison microscope, dark-field microscope, fluorescence microscope, polarizing microscope, scanning electron microscope, X-ray microscope are to magnify small objects that cannot be seen by the naked eye. Lie Detection a. Polygraph – • It is based on principle that if a person is telling lie, and if there is fear that the lie will be detected he emotional fear results in stimulation of sympathetic nervous system that causes physiological changes and some of these changes can be recorded. • Polygraphy process uses and record following parameters 1. Blood pressure 2. Pulse 3. Heart rate 4. Respiration 5. Sweating 6. Psychogalvanic reflex. Such phenomenon reflects emotional reactions which are use in detecting deception. It is popularly known as lie detector. The tracing made is called as Polygram.
- 16. b. Narcoanalysis Narcoanalysis is a procedure of investigation of mental content of a person done after application of a light general anesthetic drugs. This investigative technique is based on the principle that at a point very close to unconsciousness, the subject would be mentally incapable of resistance to questioning, and incapable of inventing falsehood that he has used to conceal his guilt. It involves administration of light anesthetic agents or drugs intravenously Drugs commonly used are 1. Thiopentone sodium (Sodium pentothal) 2. Scopolamine hydrobromide 3. Sodium secnol 4. Benzodiazepines Adverse effects of Thiopentone sodium include laryngospasm; shivering and delirium may occur during recovery It can precipitate acute intermittent porphyria in susceptible individuals.
- 17. c. Brain Mapping Brain fingerprinting determines if specific information is present in the brain of criminal regarding the criminal act It is like seeking fingerprints at the crime scene and thus the name brain fingerprinting Brain fingerprinting is an investigative technique to measure recognition of familiar stimuli by measuring electrical brain wave response to words, phrases or pictures that are presented on a computer screen Brain fingerprinting technology is based on the principle that there are brain wave responses Brain fingerprinting measures brain waves functioning to detect awareness of crime-relevant information in order to distinguish between guilt and innocent suspects