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Forensic Science. What is Forensic Science? Forensic comes from the Latin word forensis. Forensic comes from the Latin word forensis. Meaning - for public.

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Presentation on theme: "Forensic Science. What is Forensic Science? Forensic comes from the Latin word forensis. Forensic comes from the Latin word forensis. Meaning - for public."— Presentation transcript:

1 Forensic Science

2 What is Forensic Science? Forensic comes from the Latin word forensis. Forensic comes from the Latin word forensis. Meaning - for public discussion or debate. Meaning - for public discussion or debate. Any science, used for the purposes of the law, is a forensic science. Any science, used for the purposes of the law, is a forensic science.

3 Forensic Scientists Television enhances the image of forensic science. Television enhances the image of forensic science. Forensic scientists are not involved in all aspects of criminal cases. Forensic scientists are not involved in all aspects of criminal cases. Goal - use all available scientific information to determine the facts &, subsequently, the truth. Goal - use all available scientific information to determine the facts &, subsequently, the truth.

4 Forensic Scientists Scientific facts Scientific facts Based on investigation, not circumstantial evidence or the sometimes unreliable testimony of witnesses. Based on investigation, not circumstantial evidence or the sometimes unreliable testimony of witnesses. Forensic scientists can prove the existence of a crime or make connections to a crime. Forensic scientists can prove the existence of a crime or make connections to a crime.

5 Works Closely With State & Local Police & Sheriff State & Local Police & Sheriff Prosecuting and Defense Attorneys Prosecuting and Defense Attorneys Immigration workers Immigration workers Crime scene investigators Crime scene investigators DEA – Drug Enforcement Agency DEA – Drug Enforcement Agency CIA – Central Intelligence Agency CIA – Central Intelligence Agency FBI – Federal Bureau of Investigation FBI – Federal Bureau of Investigation

6 Types of Forensic Scientists Criminalistics Criminalistics - Engineering - General - Jurisprudence - Odontology - Pathology/Biology - Physical Anthropology - Psychiatry & Behavioral Science - Questioned Documents - Toxicology - Engineering - General - Jurisprudence - Odontology - Pathology/Biology - Physical Anthropology - Psychiatry & Behavioral Science - Questioned Documents - Toxicology

7 Locard Exchange Principle Locard: director of the very first crime laboratory in Lyon, France. Locard: director of the very first crime laboratory in Lyon, France.crime laboratoryLyonFrancecrime laboratoryLyonFrance Principle states that "with contact between two items, there will be an exchange Principle states that "with contact between two items, there will be an exchange Perpetrator(s) of a crime comes into contact with the scene, they will both bring something into the scene and leave with something from the scene. Perpetrator(s) of a crime comes into contact with the scene, they will both bring something into the scene and leave with something from the scene. Every contact leaves a trace. Every contact leaves a trace.

8 Eight Forensic Techniques Firearms and Tool Marks Firearms and Tool Marks Forensic Profiling Forensic Profiling Document Examination Document Examination Autopsy Autopsy DNA Typing DNA Typing Forensic Anthropology Forensic Anthropology Odontology Odontology Blood Blood

9 Firearms and Tool Marks Matching bullets to the gun that fired them. Matching bullets to the gun that fired them. Tool Marks: ID characteristics between tools and the object it was used on Tool Marks: ID characteristics between tools and the object it was used on Pry bar and door with matching imprints Pry bar and door with matching imprints Explosives and imprint evidence. Explosives and imprint evidence.

10 Firearms Gunshot residue particle analysis pertains to: Identification of bullet holes Identification of bullet holes Estimation of range of fire Estimation of range of fire Linking the suspect with the firing of a gun- in-question Linking the suspect with the firing of a gun- in-question

11 Forensic Profiling Specially trained psychiatrist or investigator can examine crime scenes to develop a personality profile of the offender. Specially trained psychiatrist or investigator can examine crime scenes to develop a personality profile of the offender. Sex Sex Age Age Occupation Occupation Lifestyle Lifestyle

12 Document Examination This discipline involves relationships that between document and inscription and how it relates to a person or sequence of events. This discipline involves relationships that between document and inscription and how it relates to a person or sequence of events. Forgery Forgery Counterfeiting Counterfeiting Handwriting analysis. Handwriting analysis.

13 Document Investigation Document examination case fall into the "white- collar crime" category Document examination case fall into the "white- collar crime" categorywhite- collar crimewhite- collar crime Include identity theft, forgery, counterfeiting, fraud, Include identity theft, forgery, counterfeiting, fraud,identity theftforgerycounterfeitingfraudidentity theftforgerycounterfeitingfraud Questioned documents are often important in so many different contexts and for so many different purposes. Questioned documents are often important in so many different contexts and for so many different purposes. May commit murder and forge a suicide note May commit murder and forge a suicide note Document being produced directly as a part of a crime Document being produced directly as a part of a crime

14 Autopsy Post mortem exam determines: Post mortem exam determines: Manner of Death Manner of Death Method of Death Method of Death Time of Death Time of Death Place of Death Place of Death

15 Death That Must be Reported & Investigated Sudden or unexpected Sudden or unexpected Suspicious circumstances Suspicious circumstances Result of an injury of Accident Result of an injury of Accident Natural death – disease or old age; Natural death – disease or old age; Unnatural death – unexpected or unnatural causes Unnatural death – unexpected or unnatural causes

16 Other Reasons for Autopsy Diagnosis Disease Diagnosis Disease Evaluate possible public health issue Evaluate possible public health issue For example, the diagnosis of Alzheimers disease can only be confirmed upon autopsy For example, the diagnosis of Alzheimers disease can only be confirmed upon autopsy

17 Autopsy Process Includes external exam and photos Includes external exam and photos Tattoos, Scars, Birthmarks, etc. Tattoos, Scars, Birthmarks, etc. Followed by extensive internal exam: Followed by extensive internal exam: Organs are removed, weighed and examined Organs are removed, weighed and examined Tissues and fluids are analyzed for abnormalities & presence of drugs Tissues and fluids are analyzed for abnormalities & presence of drugs

18 Fluids Examined Urine Urine Semen Semen Vomit Vomit Blood Blood Stomach Contents Stomach Contents Spinal Fluid Spinal Fluid Saliva Saliva

19 Medical Examiner Has the legal authority to order an autopsy without the consent of the deceased persons next of kin. Has the legal authority to order an autopsy without the consent of the deceased persons next of kin. If not ordered by Medical Examiner, MUST have permission from next of kin. If not ordered by Medical Examiner, MUST have permission from next of kin.

20 DNA Typing What is DNA? What is DNA? Nucleus of cells contain RNA/DNA Nucleus of cells contain RNA/DNA DNA has deoxyribonucleic acid. DNA has deoxyribonucleic acid. Nucleus has 23 pairs of chromosomes made up of DNA Nucleus has 23 pairs of chromosomes made up of DNA In each pair, one chromosome from sperm, one from egg In each pair, one chromosome from sperm, one from egg

21 DNA Typing Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses.nucleic acidgeneticorganisms virusesnucleic acidgeneticorganisms viruses The main role of DNA molecules is the long-term storage of information. The main role of DNA molecules is the long-term storage of information.moleculesinformationmoleculesinformation

22 DNA Typing What makes DNA individual? What makes DNA individual? Four chemicals: Four chemicals: Adenine Adenine Guanine Guanine Cytosine Cytosine Thymine. Thymine.

23 DNA Typing DNA is often compared to a set of blueprints or a recipe, or a code DNA is often compared to a set of blueprints or a recipe, or a code blueprints Contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. Contains the instructions needed to construct other components of cells, such as proteins and RNA molecules.cellsproteinsRNAcellsproteinsRNA

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25 DNA Typing Such examination can establish whether a given strand is a strand of mammalian hair (vs. a synthetic or natural fiber), is a strand of mammalian hair (vs. a synthetic or natural fiber), is a strand of human hair is a strand of human hair Is from the head or another region (pubic) Is from the head or another region (pubic) Was a living, growing hair at the time it was separated Was a living, growing hair at the time it was separated Came from a particular race of persons Came from a particular race of persons

26 DNA Typing Chemical strung together = DNA code. Chemical strung together = DNA code. DNA varies from individual to individual DNA varies from individual to individual Can link a strand of DNA to a given individual. Can link a strand of DNA to a given individual.

27 DNA Typing Where DNA is Found at the crime scene Where DNA is Found at the crime scene Specimens – blood, hair, bloodstained clothing Specimens – blood, hair, bloodstained clothing Provides powerfully compelling evidence Provides powerfully compelling evidence Look in the Bathroom Look in the Bathroom

28 Forensic Anthropology Examination of Skeletal Remains Total Bones in body, 206, Missing Bones? Total Bones in body, 206, Missing Bones? Man 12 lbs Man 12 lbs Women 10 lbs Women 10 lbs Gender Male or Female: Pelvic Girth Gender Male or Female: Pelvic Girth Race: To Some Extent Race: To Some Extent Height: Ratio of Length of Long Bones to Height Height: Ratio of Length of Long Bones to Height

29 Forensic Anthropology Age at Time of Death: Size of Bones, Closure of Epiphysis Age at Time of Death: Size of Bones, Closure of Epiphysis Cause of Death or Lifestyle: Wear and Tear, Disease Processes (arthritis, fractures) Cause of Death or Lifestyle: Wear and Tear, Disease Processes (arthritis, fractures) How a person lived; How a person lived; Debilitating illnesses (rickets, polio, healed fractures); Debilitating illnesses (rickets, polio, healed fractures); Right or left handedness Right or left handedness Clues to occupation Clues to occupation

30 Odontology Examination of Teeth No other body part lasts longer No other body part lasts longer In fires, often the only thing remaining In fires, often the only thing remaining No two people have identical teeth No two people have identical teeth Dental records are needed to compare to the evidence Dental records are needed to compare to the evidence Teeth can determine a subjects age Teeth can determine a subjects age

31 Odontology WEST WARWICK, R.I., Feb 22, 2003 Fire investigators have recovered the remains of 96 victims of a Rhode Island nightclub and were working with forensic pathologists to aid identification efforts, Fire investigators have recovered the remains of 96 victims of a Rhode Island nightclub and were working with forensic pathologists to aid identification efforts, 9 of the victims had been identified so far through dental records. 9 of the victims had been identified so far through dental records.

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34 Blood - Serology Blood type – 4 types Blood type – 4 types O, A, B, AB Rh Factor Rh Factor Female cells have Barr Body Female cells have Barr Body

35 Blood Groups Blood Group AntigensAntibodies Can Give To Can Receive From AB A & B NoneAB AB, A, B, O AAB A & AB A & O BBA B & AB B & O ONone A & B AB, A, B, O O

36 Blood Kastte - Meyer Test can determine if substance (stains) is really blood Kastte - Meyer Test can determine if substance (stains) is really blood Precipiton Test determines if it is animal or human blood Precipiton Test determines if it is animal or human blood Determine gender from blood evidence – female cells have Barr body Determine gender from blood evidence – female cells have Barr body

37 Determining Time of Death Rigor Mortis Begins 3 hours after death in face & eyelid muscles Begins 3 hours after death in face & eyelid muscles Takes 12 hours to affect entire body Takes 12 hours to affect entire body Process reverses after 36 hours. Process reverses after 36 hours. Rigor Mortis – Rigor Mortis – Nystens Law: Rigor mortis affects first the muscle of the head and spreads toward the feet.Nystens Law: Rigor mortis affects first the muscle of the head and spreads toward the feet.

38 Determining Time of Death Lividity - Hypostasis Visible 30 – 60 minutes after death Visible 30 – 60 minutes after death Red cells settle & skin below turns red Red cells settle & skin below turns red After 6 – 10 hours, color becomes permanent After 6 – 10 hours, color becomes permanent

39 Determining Time of Death Body Temperature Falls at the rate of 1 degree per hour Falls at the rate of 1 degree per hour Obesity and warm environment slows cooling Obesity and warm environment slows cooling None of these are totally reliable and can be manipulated None of these are totally reliable and can be manipulated

40 Forensic Entomologists Forensic entomologists work in classrooms, research labs & in the field. Forensic entomologists work in classrooms, research labs & in the field. Practice of studying insects has existed for centuries, but there are so many areas of the field that remain largely untapped and promising. Practice of studying insects has existed for centuries, but there are so many areas of the field that remain largely untapped and promising. If body has been moved If body has been moved How long the body has been there How long the body has been there

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42 Eyewitness Accounts It used to be thought that memories were kind of like video tapes, but we now understand that all memories are reconstructions of events. It used to be thought that memories were kind of like video tapes, but we now understand that all memories are reconstructions of events. Memory is very plastic and malleable Memory is very plastic and malleable Memories are often manipulated and greatly affected by our emotional state, personal prejudices and biases. Memories are often manipulated and greatly affected by our emotional state, personal prejudices and biases.

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