MODULE-1-FORENSIC-CHEMISTRY-AND-TOXICOLOGY.pptx

Click icon to add picture FORENSIC CHEMISTRY AND TOXICOLOGY By: LOTHES J. SAMANTE GOALS and OBJECTIVES:  Defineand discuss the meaning of criminalistics or forensic science.  To have knowledge...

Click icon to add picture FORENSIC CHEMISTRY AND TOXICOLOGY By: LOTHES J. SAMANTE GOALS and OBJECTIVES:  Defineand discuss the meaning of criminalistics or forensic science.  To have knowledge on Physical Evidence.  To know the Importance of Forensic Science. CRIMINALISTICS or FORENSIC SCIENCE  Defined as the study of criminal things.  Itinvolves the application of scientific techniques to the solution of crime. It provides a basic knowledge of physical evidence. Physical Evidence  is any object that can establish that a crime has been committed or can provide a link between a crime and its victim or between a crime and its perpetrator. Examples of Physical Evidence photography, fingerprints and other impression, ballistics, glass, hair, fiber, paint, handwriting and document examination, drugs and instrumental method of analysis.  Italso provides technique of comparing an item discovered at the scene of the crime with an item associated with or found on the suspect.  Itis also defined as the forging of many scientific disciplines into one relevant, concerted effort, under the rules of evidence, to establish circumstantially the innocence or guilt of the accused. IMPORTANCE OF FORENSIC SCIENCE Forensic science is the marriage of natural science principles and the law. In this union, forensic professionals use their scientific backgrounds to help law enforcement personnel solve crimes. FORENSIC CHEMISTRY  Is the branch of chemistry which deals with the application of chemical principles in the solution of problems arising from the administration of justice.  It is chemistry applied in the elucidation of legal problems.  It is chemistry used in courts of law.  It is chemistry that belongs to the courts of law. THE HISTORY OF FORENSIC CHEMISTRY AND TOXICOLOGY “Forensic Chemistry is the application of chemical science or chemistry in solving or proving the crime in the court of law. Chemical science is being used for the analysis of pieces of evidence found at the scene of a crime.” The history of forensic chemistry is holding the facts of methods developed by a scientist for the identification and analysis of poisons, which were used for the commission of murders. The pieces of evidence of the use of poisons come from the early Egyptians, Romans, and Greeks.  THE HISTORY OF FORENSIC CHEMISTRY AND TOXICOLOGY (1813) Mathieu Orfila - is considered the father of modern toxicology. He also made significant contributions to the development of tests for the presence of blood in a forensic context and is credited as the first to attempt the use of a microscope in the assessment of blood and semen stains. a Spaniard who became professor of medicinal/forensic chemistry at University of Paris, published Traite des Poisons Tires des Regnes Mineral, Vegetal et Animal, ou Toxicologie (General Toxicology).  THE HISTORY OF FORENSIC CHEMISTRY AND TOXICOLOGY  Democritus - was probably the first chemist to study poisons, and he communicated some of his findings to Hippocrates.  (1836) James Marsh - an Scottish chemist, was the first to use toxicology (arsenic detection) in a jury trial.  (1851) Jean Servais Stas - a chemistry professor from Brussels, Belgium, was the first to successfully identify vegetable poisons in body tissue.  (1910) Edmund Locard - professor of forensic medicine at the University of Lyons, France, established the first police crime laboratory.  (1960) Lucas - in Canada, described the application of gas chromatography to the identification of petroleum products in the forensic laboratory and discussed potential limitations in the brand identity of gasoline.  (1976) Zoro and Hadley - in the United Kingdom first evaluated chromatograph-mass spectrometry for forensic purposes.  THE HISTORY OF FORENSIC CHEMISTRY AND TOXICOLOGY  1918-(New York City)appointed the first trained medical  Charles Norris was the first appointed chief medical examiner and Alexander Gettler (chemist and partner of Norris) rewrote the rules of crime detection in America.  THE ANCIENT ISSUES IN FORENSIC CHEMISTRY AND TOXICOLOGY  Poisons were employed by early Egyptians and ancient Greeks and Romans.  Poisons were used both for murder and as a means of execution; the philosopher Socrates was condemned to death by drinking hemlock.  In Ancient Roman civilization had laws against poisoning in 82 B.C.E. Before the development of systematic, scientific criminal investigation, guilt was determined largely by circumstantial evidence and hearsay.  Arsenic was a popular poison in Roman times. It was referred to as inheritance powder in early France.  The Blandy trial of 1752 was the first instance of an actual chemical test for poison.  the Marsh test, developed in 1836, was the first reliable analysis that could show scientifically that arsenic was present in the body of a victim.  IMPORTANCE OF FORENSIC CHEMISTRY AND TOXICOLOGY  Forensicscience can solve mysteries surrounding deaths, whether the cause is natural or foul play.  Itinvolves the examination of the specimens found in the crime scene like blood, hair, and other types of fluid found that has connection to the perpetrator.  Itcan allow the authorities to do positively identify the suspect in a crime to determine exactly when and how a crime occurred. IN OTHER WORDS; The goal of forensic chemistry is to determine the provenance of a sample and link it to a person or thing. What is a crime laboratory?  Itis where the physical and chemical examination conducted. Edmond Locard  Considered as the father of the crime laboratory. Walker Mc Crone  Considered as the father of microscopic forensics. Different Units in the Crime Laboratory: 1. Physical Science Unit – identification and comparison of drugs, glass, paint, explosives and soil using chemical tests and modern analytical instruments. 2. Biology Unit – identification and grouping of dried bloodstains and other body fluids, comparison of hairs and fibers and the identification and comparison of botanical materials such as woods and plants. 3. Firearms Unit – examination of firearms, discharged bullets, cartridge cases, shotgun shells and all types of ammunition. Garments and other objects are also examined in this unit to determine the presence of discharge residues and to approximate target distance. 4. Document Examination Unit- examination of handwriting and typewriting on questioned documents to ascertain authenticity and/or source. It includes also the analysis of paper and ink and examination of indented writings, obliterations, erasures and burned or charred documents. 5. Photography Unit – aids in the preparation photographic exhibits for courtroom presentation using highly specialized photographic technique of infrared, ultraviolet and x-rays. 6. Toxicology Unit – examination of body fluids and organs for the presence or absence of drugs and poisons. 7. Latent Fingerprint Unit – processing and examination of evidence for invisible or latent fingerprints. 8. Polygraph Unit – applies the techniques of criminal investigation and interrogation. 9. Voiceprint Analysis Unit – where telephoned threats and tape-recorded messages are examined using an instrument, the sound spectrograph, that transforms speech into a visual graphic display called voiceprint. 10. Evidence Collection Unit – dispatches specially trained personnel ( civilian/ police) to the crime scene to collect and preserve physical evidence. WHO ARE EXPERT WITNESS?  Expertwitness are person who testifies his personal knowledge on certain issues in court provided he is not disqualified by law. Qualifications of an Expert Witness:  He must be competent (cite educational degrees, participation in special courses, published books and articles, membership in professional societies).  He must be experienced ( state number of years on occupational experience). FORENSIC CHEMIST Is one who practices Forensic Chemistry. Scope of Forensic Chemistry: 1. It includes the chemical side of criminal investigation. 2. It includes the analysis of any material the quality of which may give rise to legal proceedings. 3. It is not limited to purely chemical questions involved in legal proceedings. 4. It has invaded other branches of forensic sciences notably legal medicine, ballistics, questioned documents, dactyloscopy and photography. Role of Forensic Chemist in the Scientific Criminal Investigation:  Determining whether or not a place or location is a clandestine laboratory ( a secret location utilized for the purpose of producing illicit drugs or illicitly producing licit drugs.  Examining suspect’s hand and marked bills for the presence of fluorescent powder and invisible markings during extortion cases.  Taking of paraffin cast. Practice of Forensic Chemistry The work of forensic chemist is divided into four stages, namely: 1. Collection or reception of the specimen. 2. The actual examination. 3. The communication of the results of the examination. 4. Court appearance. Collection of the specimen to be examined The proper collection, preservation and transportation of specimens are essential in the investigation of crime. Hence, whenever possible, the chemist should personally collect all the specimens necessary for the examination. This particular stage of a forensic chemist’s work is essential as questions regarding the collection, preservation and transportation of the specimen are raised during trial. Factors That Must Considered When Collecting Specimen For Examinations: 1. Sufficiency of Samples 2. Standard for Comparison 3. Maintenance of Individuality 4. Labelling and Sealing Sufficiency of Samples  As much as possible, the investigator should collect sufficient amount of specimen for examination. This will make the chemist confident that in case of doubtful result, he or she can still have enough samples to repeat or to proceed to the succeeding examinations. Standard for Comparison  When the evidence in question is located in or added with foreign substance, a sample of such foreign substance must be submitted for analysis. For instance, if blood is found on linoleum, a sample of the unstained linoleum must be submitted together with the stained portion. In cases of adulteration or unfair trade competition, a genuine sample must be submitted for comparison. In the examination of hair, textile fiber, soil, etc., standard samples must be submitted for comparison.  GOLDEN RULES IN THE PRACTICE OF FORENSIC CHEMISTRY The six golden rules in the practice of forensic chemistry are; 1. Go slow 2. Be thorough 3. Take notes 4. Consult others 5. Use Imagination 6. Avoid complicated theory  GOLDEN RULES IN THE PRACTICE OF FORENSIC CHEMISTRY 1. Go slowly: good work cannot be hurried, therefore take all the time necessary to make the case complete, no matter how urgent it may appear or how pressing others may be for the result; it is generally possible to adjourn a case if work cannot be finish in time. 2. Be thorough; make a careful and minute examination of everything and do not be satisfied with a qualitative analysis if a quantitative one be possible; it always pays to do too much rather than too little and it is difficult to foresee what will or will not be required in court. 3. Take notes; keep a full, neat and clear record of everything seen and done.  GOLDEN RULES IN THE PRACTICE OF FORENSIC CHEMISTRY 4. Consult others; many cases will lead the expert into paths with which he is not familiar, and when this happen he should consult those who are most likely to know. 5. Use imagination; this is somewhat hazardous advice, since an expert with a vivid and uncontrolled imagination is a most dangerous person; a discipline imagination, how ever, which enables inferences and deductions to be made from slender and incomplete premises is often very useful. In writing the report the imagination must be kept well in hand and the expert should remember that what to him may be merely a helpful working hypothesis is liable to be taken by others for more than its true worth and to be adopted by them as a final explanation. 6. Avoid complicated theories; the simplest explanation is the most likely to be the right one. END THANK YOU….. NOTE: GET READY FOR A SHORT QUIZ, AND HAVE A NICE DAY EVERYONE…. References:  https://forensicchemistrykrystalbryant.weebly.com/history.html  https://sciencemonk.com/forensic-chemistry-applications-of-fore nsic-chemistry/  https://seak.com/blog/expert-witness/expert-witness-requiremen ts/  https://pressbooks.bccampus.ca/criminalinvestigation/chapter/ch apter-3-what-you-need-to-know-about-evidence/  https://seak.com/blog/expert-witness/expert-witness-requiremen ts/