1. General Information About Forensic Science

1. General Information About Forensic Science History & Development of Forensic Science • Criminalist: Forensic Scientist TV Forensics vs Real Forensics TV Interrogate suspects & kick down doors Reality Never interrogate suspects; often go to crime scenes long after the crime Make judgements about guilt/innocence Should never make judgements about guilt or innocence (can compromise impartially of scientist and scientific method) Operate independently of other investigators Work as part of an investigative team, usually (go to crime scenes without permission) in a subordinate role (police are ultimately in charge) Usually have multiple expertise (everyone is Usually do not have multiple expertise an expert in everything) Act like detectives (ask “why” - why would Deal with only observable and quantifiable someone do this and not that; rely on feelings) phenomena to reach theories and conclusions (see NAS report) Get DNA results in a day Get DNA results in 2-3 weeks average History & Development • Sir Arthur Conan Doyle • Sherlock Holmes • Applies new principles long before investigators used them • Serology, fingerprinting, firearm identification, and questioned document examination • A Study in Scarlet, published in 1887 Important People • Mathieu Orfila: Father of forensic toxicology (poison); 1814 book. • Alphonse Bertillon: Anthropometry (system of body measurements) for identification • Francis Galton: First definitive study and classification of fingerprints; 1892 book. • Leon Lattes: Determined blood group of dried blood; 1915. • Hans Gross: First to suggest combining police investigations and science; 1893. • Calvin Goddard: Ballistics (matching a bullet to a gun) • Albert Osborne: Document examination; 1910 Edmond Locard (1910) • Born in France. • Obtained Ph.D. in legal medicine (1902) & passed the bar exam (1907). • Works of Hans Gross and Conan Doyle inspired Locard to travel to major cities of the world to study police agencies and crime science. • Incorporated the scientific method and trace evidence analysis for crime scene investigation and reconstruction crime scenes. • Started the first crime lab. Federal Bureau of Investigation • In 1932 under the directorship of J. Edgar Hoover, a national laboratory was established to offer forensic services to all law enforcement agencies in the country. • The FBI lab is the largest forensic science lab in the world. • Performs over one million examinations every year. • The FBI’s Forensic Science Research and Training Center was established in 1981. • Conducts experiments to develop new and reliable scientific methods that can be applied to forensics. • Trains other crime lab personnel. • Crime Lab Services: • Physical science, biology, firearms, document examination, photography, fingerprint, ballistics, polygraph, voice analysis, evidence collection, trace evidence, arson, toxicology, computer crimes • Scientific Forensic Services: • Pathology, anthropology, entomology, psychiatric, odontology • Engineering, accounting, documents, chemistry, biology, botany Frye vs United States (1923) • In rejecting the scientific validity of the lie detector (polygraph) in 1923, the District of Columbia Circuit Court set forth what has since become the standard guideline for determining the judicial admissibility off scientific examinations. • To meet the Frye standard, the court must decide if the questioned procedure, technique, and principles are “generally accepted” by a meaningful segment of the relevant scientific community. Daubert vs Merrel Dow (Pharmaceutical 1993) • Judge determined admissibility of scientific evidence based on expert testimony. • Judges did a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically relevant and reliable. Determining Admissibility • Judges must consider: • If the information in question could be/has been tested. • If the theory of technique went through peer review and publication. • The known or potential rate of error. • If the theory or technique has gained general acceptance in the relevant scientific area. Expert Witness Testimony • To qualify as an expert witness: • Education/higher decrees • Experience in field • Published • Professional organizations • Voir dire: A process by which an expert witness establishes their qualifications The Crime Scene Notes • Forensic Science begins at the crime scene • If you mess up, you probably can’t fix it • You only get 1 chance • Look for: • What is there that should not be there - Obvious items that stand out • What is not there that should be there - Subtle things that indicate something is not right • Types of Crime Scenes: • Outdoor: Small area or miles long • Indoor: Easier to control (fewer environmental issues, but more crowded with personnel) • Conveyance: Involves transportation • Primary Crime Scene: Where the crime took place • Secondary Crime Scene: Anywhere the crime touches • Crime Scene Investigations • Recognition: Crime Scene Survey, Documentation, Collection, Preservation • Identification: Comparison Testing • Individualization: Evaluation, Interpretation • Reconstruction: Reporting, Presentation Processing The Crime Scene • Secure and Isolate: Preserve and Protect the Scene • Make scene safe, provide medical attention, establish perimeter (overestimate; may need to be multi-level), focus on 3 dimensions, establish ingress/egress point, assign officer to log all personnel in and out • Walk-Through • Record the Scene • Photography: Overview (whole scene) & Itemized (specific item); Photo Log • Sketches: Rough (with measurements) & Finished (scaled - shows where everything is in relation to everything else • Notes • Search for Evidence: Establish search patterns • Collect and Package: Always use paper bags (except for arson evidence - use airtight canisters) • Never shred or destroy evidence • Chain of Custody: Documentation of the life of evidence (protects integrity of evidence) • Obtain Controls & Submit Evidence: Transfer evidence to a lab (limited access vaults); complete paperwork • Crime Scene Safety: Always wear gloves • Legal Considerations: Obtain a search warrant (4th Amendment) • Warrantless Searches: • Exigent (urgent) circumstances • Plain view • Probable cause (has/will commit a crime) • Prevent from destroying evidence (needs of society > needs of individual) • Safety of officer Sketches • Know where everything is in relation to everything else • Rough Sketch: Include measurements • Final Sketch: Proportionate (measurements are not always included) • Not always made • Basic Case Information: Time, Date, Location • Measure 90º from wall to object • Black Line Drawing: Shown instead of pictures sometimes • Pictures are distracting and induce emotion • Triangulation Measurement: Measure item based off two fixed points Rough vs Final Sketch • Walls, big trees, building corner, telephone pole, street lamp, 32282/"https://slideplayer.com/sli fire hydrant, sewer grate • Baseline Measurement: Run tape measure (baseline) along crime scene, measure from baseline to item • Measure in a straight line from a fixed object • Laser Scanner: Creates replica of crime scene • Gives all measurements, marks evidence points • 3D Diorama Physical Evidence • Impossible to list all objects that could be important to a crime. • Almost anything can be physical evidence. • Physical evidence is collected and analyzed. • A jury ultimately decides the importance of a piece of evidence in a case. Examples of Physical Evidence • Objects: Tools, firearms, displaced furniture, notes/letters, vehicles, cigarettes, weapons, documents, drugs, explosives, fibers, glass, paint, petroleum products, plastic bags, rubber polymers, powder residues, serial numbers, soil, vehicle lights, wood/vegetative matter. • Body Materials: Blood, semen, hair, tissue, saliva, urine, feces, vomit, hair, organs, fluids. • Impressions: Fingerprints, tire tracks, shoe prints, toolmarks, bullet holes, dents, scratches, newly damaged areas. Class Characteristics • Characteristics shared by at least one other item. • Many are part of the manufacturing process: size, spacing, tread design, etc. Individual Characteristics • Characteristics that are unique and random. • Establishes a link between a questioned impression and one object. Wear Characteristics • Changes in the surface of an object due to the erosion of portions of the surface. • Not individualizing - Possible for two or more things to wear in similar manners Forensic Databases • The Integrated Automated Fingerprint Identification System (IAFIS): National fingerprint & criminal history system, FBI • The Combined DNA Index System (CODIS): Crime laboratories can electronically exchange and compare DNA profiles • The National Integrated Ballistics Information Network (NIBIN): Firearm markings on bullets and cartridge casings • The International Forensic Automotive Paint Data Query (PDQ): Chemical and color information for original automotive paints • Shoeprint Image Capture and Retrieval: (SICAR): Shoe Print database CSI Effect • Prosecutor’s believe that crime programs are skewing juror’s courtroom expectations, ultimately making it more difficult to win their cases and convict defendants. • Some believe technology in general is at fault, but the belief is persistent - crime programs (e.g. CSI) are influencing jurors and the courtroom. • Studies suggest that regular CSI viewers have higher expectations for courtroom evidence. Negative Effects 1. More difficult to prosecute defendants • Jurors want more hard evidence (e.g. smoking gun & DNA proof), which doesn’t always exist. • Circumstantial evidence and eye-witness accounts are not good enough (jurors want sophisticated science in every trial). 2. Harder to find jurors • Some states allow lawyers to dismiss potential jurors from the pool based on the TV programs they watch. • Flag or remove jurors who frequently watch crime programs. 3. Straining already tight resources • Some investigators run useless tests to get more evidence to strengthen their case and satisfy jury members. • Wastes money and time. 4. Manipulating crime scenes • Criminals use crime shows to help them not get caught (e.g. wear gloves, bleach incriminating evidence). 5. Defense lawyers are spending too much time educating juries • Defense teams must present and explain forensic evidence to juries, who have difficulty understanding it. • Calculated in probabilities rather than certainties Positive Effects 1. Jurors are becoming more knowledgeable • CSI-viewers show patterns of higher legal knowledge (expect relevant evidence and dismiss irrelevant evidence). 2. Interest is increasing in the criminal justice field • Raises interest and awareness to legal, medical, and investigative professionals and their work (potential jobs).