Introduction to Forensic Science F23 PDF

Lecture # 1 Introduction to Forensic Science FOS 706 Physical & Biological Evidence Professor Linda Rourke 1 2 Blackboard Website n n Must have access to CUNYfirst account Blackboard site access requires same login credentials as CUNYfirst n n Professional Organizations  Different from you...

Lecture # 1 Introduction to Forensic Science FOS 706 Physical & Biological Evidence Professor Linda Rourke 1 2 Blackboard Website n n Must have access to CUNYfirst account Blackboard site access requires same login credentials as CUNYfirst n n Professional Organizations  Different from your email log-in credentials  Check JJC email regularly n Announcements, assignments, etc. will be posted throughout semester n NEAFS (Northeastern Association of Forensic Scientists) n www.neafs.org n Annual NEAFS Meeting: usually in October or November in a location in the Northeast AAFS (American Academy of Forensic Sciences) n www.aafs.org n Annual Meeting usually held during the third week in February, various locations NYMS n n 3 4 DEFINITIONS n n 5 New York Microscopical Society www.nyms.org FORENSIC SCIENCE What is forensic science? What is criminalistics? De Forest, Gaensslen & Lee: “Forensic science is the application of the natural sciences to matters of the law” 6 1 CRIMINALISTICS FORENSIC SCIENCE CAC: Criminalistics is “that profession and scientific discipline directed to the recognition, identification, individualization, and evaluation of physical evidence by the application of natural sciences to lawscience matters.” 7 n n 8 SCIENTIFIC METHOD n n n n SCIENTIFIC METHOD A way of thinking. Problem Solving. Understanding a phenomenon. Generally, a stepwise approach. 1. 2. 3. 4. 5. 9 Observation Conjecture Hypothesis Testing Theory 10 LEGAL SYSTEM n n n SCIENCE & LAW Set of rules governing human interactions & behavior to facilitate society harmony Criminal Codes n Forensic science developed out of a common interest in factual information. Governs activities in which society as a whole has an interest Different approaches to fact-finding by scientists and lawyers in an adversarial system. Civil Codes n 11 Draws upon the principles and methods of traditional sciences Unique objectives: continuous & necessary interaction with legal system Govern relations between individuals and groups 12 2 HISTORY OF FORENSIC SCIENCE Branches of Forensic Science n n n n n n n n Criminalistics Forensic Medicine Forensic Odontology Forensic Anthropology Forensic Toxicology Questioned Documents Examination Firearm & Toolmark Analysis Fingerprint Examination 13 Began with scientific inquiry into legal concerns Early use of fingerprints, 700s n From fiction to reality, 1800s n n n Babylonians, Chinese Edgar Allan Poe: Auguste Dupin A.C. Doyle: Sherlock Holmes 14 Locard Exchange Principle Edmond Locard: “No one can act with the force that the criminal act requires without leaving behind numerous signs of it: either the wrong-doer has left signs at the scene of the crime, or, on the other hand, has taken away with him – on his person or clothes – indications of where he has been or what he has done.” Locard Exchange Principle This passage has been summarized as: “every contact leaves a trace.” According to the Locard exchange principle, there is always a mutual exchange of material when two objects come into contact, whether or not this mutual exchange can be detected using scientific methods. http://www.microtracescientific.com/labr atory/lineage/locard.htm 22 http://www.microtracescientific.com/labr atory/lineage/locard.htm 23 n n n n n n 24 n U.S. History of Forensic Science Organization of Crime Labs 1907 - August Vollmer used services of a scientist in a homicide trial 1923 - Vollmer created oldest forensics lab in the U.S., in Berkeley 1930-32 - State labs set up in California 1932 - FBI lab established under directorship of J. Edgar Hoover 1937 - Criminalistics program set up at Univ. of CA, Berkeley, by Paul Kirk 1981 - FBI’s Forensic Science Research and Training Center opened Federal system of government; local law enforcement agencies prefer to maintain control over their jurisdiction. n Federal crime labs n State Labs n n Regional Labs Local Labs 25 3 Major Federal Forensic Labs n n n n n Major Federal Forensic Labs Federal Bureau of Investigation (FBI) Drug Enforcement Agency (DEA) Bureau of Alcohol, Tobacco and Firearms U.S. Postal Inspection Service U.S. Secret Service Forensic Services n n n n n n n 26 Environmental Measurements Laboratory National Biodefense Analysis and Countermeasures Center Plum Island Animal Disease Center Transportation Security Laboratory U.S. Food & Drug Administration Lab And more… 27 Role of the Forensic Scientist n n n What does the forensic scientist do? Almost anything can become physical evidence. The forensic scientist must be able to recognize physical evidence, and must decide what kind of tests, measurements or analyses on a particular piece of evidence will be the most informative under the particular circumstances Has no control over the condition or history of the sample. 28 n Identification n n What type of material are we dealing with? Identify by class characteristics 29 What does the forensic scientist do? n What does the forensic scientist do? Individualization (controversial) n Demonstration of the uniqueness of the sample; also demonstrate common origin between questioned and known samples; usually only partial individualizations (refined IDs) are possible. Error associated with all measurements in science: individualizations are associated with compellingly small errors 30 Homeland Security Labs Reconstruction the process of putting the pieces of a case or situation together with the objective of reaching an understanding of a sequence of past events based on the record of physical evidence that has resulted from these events. 31 4 Professional Issues n Professional Issues Ethics n Scientific work ethic – at the lab bench Working with agents of the legal system n Court Testimony Quality Assurance Accreditation: for the forensic laboratory Certification: for the forensic scientist n Proficiency Testing: for the forensic scientist n n n n https://www.netflix.com/title/80233339 https://apnews.com/article/henry-lee-fabricated-murderevidence-ef08de1e15148b3d48129ead10924009 32 33 Daubert v. Merrell Dow Pharmaceuticals Significant Legal Cases n Frye v. United States (1923) n Early lie detector test admissibility case n “General acceptance in the relevant scientific community.” n n n n Daubert v. Merrell Dow Pharmaceutical, Inc. (1993)…. n Federal court case - 1993 Provided guidelines for admissibility of scientific evidence in federal courts. Many state courts have adopted Daubert guidelines. Where Science Enters the Courtroom, the Daubert Name Looms Large n 34 35 Daubert Admissibility Guidelines n n n n n 36 https://undark.org/2020/02/17/daubertstandard-joyce-jason/ Daubert v. Merrell Dow Pharmaceuticals Is the scientific methodology testable? (Can experiments be performed to test the methodology?). Are there standardized procedures for the scientific methodology ? Does the scientific methodology have known error rates? Is the scientific methodology peer reviewed? Is the scientific methodology generally accepted by the relevant scientific community? n n The judge must act as the gatekeeper for admissibility of scientific and technical expert testimony. New legislation pending in 2023 to reinforce this role: n https://news.bloomberglaw.com/bloomberglaw-analysis/analysis-say-goodbye-todaubert-motion-hello-to-new-rule-702 37 5 Forensic Science Involvement In Criminal Cases n n n n Depends on the type of crime Cost efficiency Decisions regarding the extent of physical evidence involvement in cases Knowledge of police and attorneys in abilities and scope of science 38 PHYSICAL EVIDENCE 39 Physical evidence can reveal: n Info On Corpus Delicti (the body of the crime) n n Physical evidence can: n the essential facts indicating that a crime has occurred. n Info On Modus Operandi (method of operation) n Link A Suspect With A Victim n Link A Person To A Crime Scene n establish MO from physical evidence: means of entry, tools used, arson accelerant used, etc. 40 fingerprints, blood, semen, hairs, fibers, soil, bullets, cartridge cases, toolmarks, footprints, tire tracks, etc. 41 Physical evidence can: n n Physical evidence can: Disprove Or Support A Witness’ Testimony n n Provide Investigative Leads n physical evidence must be consistent with a person’s version of the story; blood species, etc. n direct investigation along a productive path; i.e. paint chip from car. Exonerate the innocent n Identify A Suspect n 42 esp. in violent crimes; blood, hairs, fiber transfers; trace evidence analysis. DNA evidence: The Innocence Project (really an individualization) -Fingerprints 43 6 Forensic Analysis of Physical Evidence n n n Forensic Analysis of Physical Evidence Comparison between questioned and known samples in an attempt to associate the two Type of evidence determines the extent of info obtainable and conclusions drawn Three possible outcomes… 44 n n n Match in all properties used to compare them; common origin possible. No match; possibility of common origin excluded; nonassociation is strong exculpatory evidence. Insufficient sample to make a conclusive comparison. 45 Forensic Analysis of Physical Evidence n n Keep in mind degree of individualization possible Statistical comparisons! 46 CRIME SCENE 53 GENERAL CRIME SCENE PROCEDURE GUIDELINES CRIME SCENE n n n n 54 Recognition of Physical Evidence - begins at the crime scene Due to limited resources/personnel, only serious crimes are fully processed. “Forensic science begins at the crime scene.” NOT at the forensic lab. No two crime scenes are exactly the same; therefore there is no specific “checklist method” for finding evidence, etc. PROTECTION OF THE SCENE n Responding officer must secure/isolate the area n n n n Only those persons who can make a contribution to the scene should be admitted. Avoid “cleaning up” the crime scene. Never bring a suspect back to the scene of the crime; it compromises any evidence obtained. 55 7 GENERAL CRIME SCENE PROCEDURE GUIDELINES GENERAL CRIME SCENE PROCEDURE GUIDELINES RECOGNITION n Decisions as to what may be important evidence should be made by an experienced crime-scene investigator who has knowledge of the capabilities of the lab. Careful observation is required; try to recognize normal and abnormal conditions. n n 56 DOCUMENTATION n Should be done in a bound notebook; record all pertinent details. Can include photography, sketches, video recording. Should include information regarding the overall scene, including any signs of disturbance, missing and found objects, climatic conditions. n n 58 GENERAL CRIME SCENE PROCEDURE GUIDELINES GENERAL CRIME SCENE PROCEDURE GUIDELINES SEARCHES n n n n SEARCHES n Mental reconstruction may help determine if certain items are missing: weapons, tools, expended cartridge cases, broken fragments from a freshly fractured surface. Protection of evidence during searches Search should be documented properly. Focus on points of entry & exit as well as target areas. n Search patterns: organized and focused n n Outdoor scenes n n n Strip Grid Spiral http://www.ssg-inc.net/cyber_crime/search.html 59 60 GENERAL CRIME SCENE PROCEDURE GUIDELINES GENERAL CRIME SCENE PROCEDURE GUIDELINES SEARCHES n COLLECTION - Depends on the type of evidence. n Search patterns n n Indoor scene: n Collection Methods: n quadrant/ zone n n n n n n 61 Visual Inspection Tape Lifts Packaging and Submission Without Sampling Vacuuming Certain types of evidence require that a substrate control also be obtained. Collection process should be well documented. 62 8 GENERAL CRIME SCENE PROCEDURE GUIDELINES GENERAL CRIME SCENE PROCEDURE GUIDELINES MARKING & PACKAGING OF EVIDENCE n n n n n Marking: done to identify it & distinguish it from others. Should be done without compromising the evidence. Packaging: done to protect the evidence and preserve its integrity; should minimize damage/contamination - Chain of Custody 63 TRANSPORTATION/STORAGE n n Avoid damage of fragile items. Maintain both legal & scientific integrity 64 GENERAL CRIME SCENE PROCEDURE GUIDELINES EVIDENCE SUBMISSION TO THE LAB n n Proper documentation of transfer - chain of custody 65 9