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Chapter 1 - Introduction
Basics of Forensic Science
Definition and Scope Forensic science is the application of
science to law: Applies the knowledge and
technology of science to the definition and enforcement of laws
Laws are continually being broadened and revised to address the alarming increase in crime rates
The Role of Science Science cannot offer final and
authoritative solutions to all problems
Social and psychological factors are always present
Science plays an important and unique role in the criminal justice system – ability to supply accurate and objective information that reflects events that have occurred at a crime scene
Definition of Forensics Science
The application of science to the to the criminal and civil laws that are enforced by police agencies in a criminal justice system.
Diversity of Professions Involved According to the American Academy of Forensic
Science: Criminalistics (synonym for forensic science) Engineering Science General Jurisprudence Odontology Pathology/Biology Physical Anthropology Psychiatry/Behavioral Science Questioned Documents Toxicology
Additions to the list of 10:
Fingerprint examination Firearm and tool mark
examination Technology analysis
Computers Digital data analysis
Photography
History and Development Individuals who developed the
principles and techniques needed to identify or compare physical evidence
Those who recognized the need to merge these principles into a coherent discipline that could be practically applied to a criminal justice system
Early Developments One of the earliest records:
3rd century China – manuscript Yi Yu Ji Case solved where a woman was suspected
of murdering her husband Evidence showed that he was murdered
and she admitted her guilt Chinese were also the first to recognize the
potential of fingerprints for identification purposes
Often the exception rather than the rule for criminal investigations
Early Developments (continued…)
Limited knowledge of anatomy and pathology Hampered the development of
Forensic Science until late 17th and early 18th centuries
First recorded notes about fingerprint characteristics 1686, Marcello Malpighi Did not acknowledge the value of
fingerprints as a method of ID
Initial Scientific Advances
1798; “A Treatise on Forensic medicine and Public Health” François-Emanuel Fodéré
Breakthroughs in chemistry also helped 1775; Carl Wilhelm Scheele devised
first successful test for detecting arsenic in dead bodies
Initial Advances (continued…) 1814; Mathieu Orfila
Father of forensic toxicology Published the first scientific treatise
(study) on the detection of poisons and their effects on animals
Mid-1800s Advance of several scientific disciplines
which advanced the field of forensics 1828; William Nichol – polarizing microscope 1839; Henri-Louis Bayard – microscopic detection of sperm 1839; toxicological evidence first used at a trial 1853; microcrystalline test for hemoglobin 1863; first presumptive test for blood 1850s and 1860s; use of photography in forensics
Late 19th-Century Progress Beginning to apply knowledge from all
scientific disciplines to the study of crime
Anthropology/Morphology (structures of living organisms) applied to the first system of personal identification 1879; Alphonse Bertillon Named anthropometry – systematic
procedure for using a series of body measurements as a means of distinguishing one person from another (later replaced by fingerprinting)
Father of Criminal Investigation
More on the 19th century…
Bertillon’s anthropometry later replaced by fingerprinting Thomas Taylor (American) said that
fingerprints could be used for ID Supported by Scottish physician
Henry Faulds 1892; Francis Henry Gaulton
undertook the first definitive study of fingerprints and developed a method for classifying them
Sherlock Holmes Not a real person Legendary but fictional detective in
stories by Sir Arthur Conan Doyle Had a considerable influence on
popularizing crime-detection methods Applied newly developing principles of
serology (blood/body fluids), fingerprinting, firearms ID and document analysis in his stories
Doyle’s “A Study in Scarlet” is a classic example (see excerpt)
20th Century Breakthroughs 1901; Karl Landsteiner
Discovered ABO blood types 1910; Albert S. Osborne
Wrote the first significant text on Questioned Documents (document examination)
1915; Dr. Leon Lattes Developed a simple procedure for identifying
the blood group from a dried blood stain Immediately applied to criminal investigations Acceptance of documents as scientific evidence
by the courts 1923; Calvin Godddard
Used comparison microscope to refine techniques of firearms examination
Edmond Locard French Formal education in both medicine and law Started the first police lab in 1910 Founder and director of the Institute of
Criminalistics @ the University of Lyons (France) Leading international center for study and
research in forensic science Strongly believed every criminal can be
connected to a crime by dust particles carried from the crime scene
Locard’s successes helped start police labs in Vienna, Berlin, Sweden, Finland and Holland
Locard’s Exchange Principle
When two objects (or people) come in contact with each other, a cross-transfer of materials occurs
Modern Scientific Advances
Mid-20th century Revolution in computer technology Dramatically impacted the field of forensics Wide array of sophisticated techniques for
analyzing evidence available Chromatography Spectrophotometry (measuring the
absorption/reflection of light by materials) Electrophoresis
DNA Most significant modern advance DNA typing and profiling 1984; Sir Alec Jeffries developed the
first DNA profiling test 1986; DNA profiling used to solve the
“Pitchfork” murders of two young English girls (Colin Pitchfork)
Precise ID of a suspect can be determined
Computer Databases
Fingerprints Bullets and shell casings DNA
Significantly reduced the time it takes to analyze evidence and increase accuracy of the results
Key Points: Forensic science is the application of science to
criminal and civil laws that are enforced by police agencies in a criminal justice system
The first system of criminal ID was called anthropometry. It distinguished one individual from another based on a series of body measurements
Forensic science owes its origins to individuals such as Bertillon, Gaulton, Lattes, Goddard, Osborne and Locard, who developed the techniques needed to identify or compare physical evidence.
Locard’s Exchange Principle states that when two objects come in contact with each other, a cross-transfer of materials occurs that can connect a criminal suspect to his/her victim.
Crime Laboratories - History 1923; Los Angeles Police Dept. crime lab is the
oldest Established by August Vollmer
1948; School of Criminology formed at UC-Berkley
1932; FBI established under President Herbert Hoover Offered forensic services to all law enforcement
agencies in the USA 1981; Forensic Science research and Training
Center for research and development of new techniques/tools/methods
Train lab personnel in the latest techniques Most labs are run locally or at the state level
Organization of a Crime Lab Characterized by rapid growth Lack of national/regional
planning/coordination Levels: federal, state, county,
municipal Size and diversity makes it impossible
to adopt a single model of operation Most function as part of the local
police department, prosecutor, district attorney or medical examiner (coroner)
Growth Several reasons explain the rapid
growth of crime labs in the past 40 years Supreme Court decisions requiring
scientific, objective treatment of evidence Constitutional rights of suspects (Miranda
Rights) Changing judicial requirements due to the
staggering increase in crime rates in the USA, especially drug-related crime
DNA technology/profiling needs more qualified personnel to analyze the evidence
Drug cases still outnumber DNA cases
Crime Labs in the USA
Desire to retain local control Produced a variety of
independent labs Government has no single law
enforcement agency with unlimited jurisdiction
Crime Labs in the USA (continued)
1. FBI (Department of Justice) Maintains the largest crime lab in the world Ultramodern facility located in Quantico, VA
2. DEA (Drug Enforcement Administration - (Department of Justice)
Analyzes drugs seized in violation of federal laws regulating production, sale and transport
3. ATF (Alcohol, Tobacco and Firearms) Analyzes alcoholic beverages Examines documents related to alcohol and firearm excise tax
law enforcement Examines weapons, explosive devices and related evidence
Gun control Act of 1968 Organized crime Control Act of 1970
4. U.S. Postal Service Criminal investigations related to the postal service
Local and International Crime Labs Most state governments maintain a
crime lab some wit regional or satellite offices (larger states) Try to be cost-effective by not duplicating
services Most countries have created and
maintain facilities Organization can vary from country to
country Often operate on a fee-for-service basis
(some can be private companies)
Services of the Crime Lab Wide variation in total services
offered There are many reasons for this
Variations in local laws Different capabilities/functions of the
organization to which the lab is attached
Budgetary and staffing limitations (often very limited)
Some labs have strict functions like processing drug specimens only
Basic Services Physical Science Unit
Principles of chemistry, physics and geology ID/comparison of crime-scene evidence
Biology Unit Biologists/biochemists DNA profiling, ID/comparison of biological evidence including
botanical materials Firearms Unit
Examines firearms, discharged bullets, cartridge cases, shotgun shells, ammunition, residues, tool marks
Determine composition, distance, angles Document Examination Unit
Handwriting/typewriting on questioned documents Ascertain authenticity/source
Photography Unit Examines/records photographic evidence Uses highly specialized techniques such as digital imaging, IR,
UV, X-ray to make invisible images/information visible
Optional Services Provided by a Full-service Crime Lab
Toxicology Unit Examines body fluids/organs to determine the
presence/absence of drugs Latent Fingerprint Unit
Processes and examines fingerprint evidence Polygraph Unit
Lie detecting Voiceprint Analysis Unit
Involves cases of telephone threats or recorded messages
Trained analysts tie the voice to a suspect Sound spectrograph creates a voiceprint Sound patterns produced in speech are unique
Optional Services (continued) Crime-Scene Investigation Unit
Dispatched specially trained personnel to a crime scene to collect/preserve evidence to be analyzed later in the lab Includes forensic pathology, entomology and anthropology
Forensic Psychiatry Examines the relationship between human behavior and legal
proceedings Behavior patterns of criminals/behavior profile
Forensic Odontology ID victims based on dental evidence Bite mark analysis linked to tooth structure on a suspect
Forensic Engineering Failure analysis, accident reconstruction, causes/origins of
fires/explosions Forensic Computer/Digital Analysis
Identifying, collecting, preserving and examining information derived from computers/digital devices
Key Points: The development of crime labs in the USA has been characterized
by rapid growth accompanied by a lack of national and regional planning and coordination
Four major reasons for the increase in the number of crime labs in the USA since the 1960s are as follows:1. The fact that the requirement to advise criminal suspects of their
constitutional rights, right to immediate access to counsel has all but eliminated confessions as a routine investigative tool;
2. The staggering increase in crime rates in the USA3. The fact that all illicit drug seizures must be sent to a lab for
confirmatory chemical analysis before a case can go to court;4. The advent of DNA profiling
The technical support provided by crime labs can be assigned to 5 basic services:
Some crime labs offer optional services such as toxicology, fingerprint analysis, polygraph administration, voiceprint analysis, and crime-scene investigation.
Special forensic services available to the law enforcement community include forensic pathology, entomology, psychiatry, odontology, engineering, computer/digital analysis.
Functions of the Forensic Scientist
Analyzing Physical Evidence Apply principles of physical/natural
sciences in analyzing evidence Only physical evidence is free of
error/bias Must undergo scientific inquiry – the
integrity of evidence comes from applying the scientific method Not tainted by human error/distortion
of facts
Functions of the Forensic Scientist (continued)
Determining the admissibility of evidence Frye vs. The United States
Procedures/techniques/principles are “generally accepted” by the scientific community
Federal Rules of Evidence Governs admissibility of evidence including
expert testimony on a scientific/technical matter if:1. Testimony is based on sufficient facts/data2. Testimony is the product of reliable
principles/methods3. Witness has applied the principles/methods
reliably to the facts of the case(also used in state courts)
Functions of the Forensic Scientist (continued)
Judging Scientific Evidence Judge assumes ultimate responsibility for
admissibility/reliability of evidence The Court offers some guidelines
1. Whether the scientific technique/theory can be tested2. Whether the scientific technique/theory has been subject of
peer review/publication3. Technique’s potential rate of error4. Existence/maintenance of standards controlling the technique’s
operation5. Whether the scientific technique/method has attracted
widespread acceptance within the relevant scientific community
Providing Expert Testimony Performing the analysis of evidence May be required to testify in court about their methods, etc. Education/training is very important
Key Points: A forensic scientist must be skilled in applying
the principles and techniques of the physical/natural sciences to analyzing evidence that may be recovered during a criminal investigation.
The cases Frye vs. the United States and Daubert vs. Merrell Dow Pharmaceuticals, Inc. set guidelines for determining the admissibility of scientific evidence into the courtroom.
An expert witness evaluates evidence based on specialized training/experience.
Forensic scientists participate in training law enforcement personnel in the proper recognition, collection and preservation of physical evidence.
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