Define Forensic Science . . .
Although there are
numerous ways by which to categorize the forensic science disciplines, the following
is the categorization used by the National Institute of Justice:
1. general
toxicology;
2. firearms/toolmarks;
3. questioned
documents;
4. trace
evidence;
5. controlled
substances;
6. biological/serology
screening (including DNA analysis);
7. fire
debris/arson analysis;
8. impression
evidence;
9.
blood pattern analysis;
10. crime scene investigation;
11. medicolegal death investigation;
and
12. digital evidence.
Forensic pathology is
considered a subspecialty of medicine.
The term “forensic
science” encompasses a broad range of disciplines, each with its own distinct
practices. The forensic science disciplines exhibit wide variability with
regard to techniques, methodologies, reliability, level of error, research,
general acceptability, and published material. Some of the disciplines are
laboratory based (e.g., nuclear and mitochondrial DNA analysis, toxicology, and
drug analysis); others are based on expert interpretation of observed patterns
(e.g., fingerprints, writing
samples, toolmarks,
bite marks). Some activities require the skills and analytical expertise of
individuals trained as scientists (e.g., chemists or biologists); other
activities are conducted by scientists as well as by individuals trained in law
enforcement (e.g., crime scene investigators, blood spatter analysts, crime
reconstruction specialists), medicine (e.g., forensic pathologists), or
laboratory methods (e.g., technologists).
Errors and Fraud
In recent years, the
integrity of crime laboratories increasingly has been called into question,
with some highly publicized cases highlighting the sometimes lax standards of
laboratories that have generated questionable or fraudulent evidence and that
have lacked quality control measures that would have detected the questionable
evidence. In one notorious case, a state-mandated review of analyses conducted
by West Virginia State Police laboratory employee Fred Zain revealed that the
convictions of more than 100 people were in doubt because Zain had repeatedly
falsified evidence in criminal prosecutions. At least 10 men had their
convictions overturned as a result.25 Subsequent reviews questioned whether
Zain was ever qualified to perform scientific examinations.
Other scandals, such
as one involving the Houston Crime Laboratoryin 2003, highlight the sometimes
blatant lack of proper education and training of forensic examiners. In the
Houston case, several DNA experts went public with accusations that the
DNA/Serology Unit of the Houston Police Department Crime Laboratory was
performing grossly incompetent work and was presenting findings in a misleading
manner designed to unfairly help prosecutors obtain convictions. An audit by
the Texas Department of Public Safety confirmed serious inadequacies in the
laboratory’s procedures, including “routine failure to run essential scientific
controls, failure to take adequate measures to prevent contamination of
samples, failure to adequately document work performed and results obtained,
and routine failure to follow correct procedures for computing statistical
frequencies.”
The Innocence Project
has documented instances of both intentional and unintentional laboratory
errors that have lead to wrongful convictions, including:
• In the
laboratory—contamination and mislabeling of evidence.
• In information
provided in forensics reports—falsified results (including “drylabbing,” i.e.,
providing conclusions from tests that were never conducted), and
misinterpretation of evidence.
• In the
courtroom—suppression of exculpatory evidence; providing a statistical
exaggeration of the results of a test conducted on evidence; and providing
false testimony about test results.
Assertions of a “100
percent match” contradict the findings of proficiency tests that find
substantial rates of erroneous results in some disciplines (i.e., voice identification,
bite mark analysis).
In a FBI publication
on the correlation of microscopic and mitochondrial DNA hair comparisons, the
authors found that even competent hair examiners can make significant errors.
In this study, the authors found that in 11 percent of the cases in which the
hair examiners declared two hairs to be “similar,” subsequent DNA testing
revealed that the hairs did not match, which refers either to the competency or
the relative ability of the two divergent techniques to identify differences in
hair samples, as well as to the probative value of each test.
The insistence by
some forensic practitioners that their disciplines employ methodologies that
have perfect accuracy and produce no errors has hampered efforts to evaluate
the usefulness of the forensic science disciplines.
And, although DNA
analysis is considered the most reliable forensic tool available today,
laboratories nonetheless can make errors working with either nuclear DNA or
mtDNA—errors such as mislabeling samples, losing samples, or misinterpreting
the data.
No forensic method
other than nuclear DNA analysis has been rigorously shown to have the capacity
to consistently and with a high degree of certainty support conclusions about
“individualization” (more commonly known as “matching” of an unknown item of
evidence to a specific known source). In terms of scientific basis, the
analytically based disciplines generally hold a notable edge over disciplines
based on expert interpretation.
The “CSI Effect”
Media attention has
focused recently on what is being called the “CSI Effect,” named for popular
television shows (such as Crime Scene Investigation) that are focused on police
forensic evidence investigation. The fictional characters in these dramas
often present an unrealistic portrayal of the daily operations of crime scene
investigators and crime laboratories (including their instrumentation,
analytical technologies, and capabilities).
Cases are solved in
an hour, highly technical analyses are accomplished in minutes, and laboratory
and instrumental capabilities are often exaggerated, misrepresented, or
entirely fabricated. In courtroom scenes, forensic examiners state their
findings or a match (between evidence and suspect) with unfailing certainty,
often demonstrating the technique used to make the determination. The dramas
suggest that convictions are quick and no mistakes are made.
The CSI Effect
specifically refers to the real-life consequences of exposure to Hollywood’s
version of law and order. Jurists and crime laboratory directors anecdotally
report that jurors have come to expect the presentation of forensic evidence in
every case, and they expect it to be conclusive.
A recent study by
Schweitzer and Saks found that compared to those who do not watch CSI, CSI
viewers were “more critical of the forensic evidence presented at the trial,
finding it less believable. Forensic science viewers expressed more confidence
in their verdicts than did nonviewers.”
Prosecutors and
defense attorneys have reported jurors second guessing them in the courtroom,
citing “reasonable doubt” and refusing to convict because they believed that
other evidence was available and not adequately examined.
Schweitzer and Saks
found that the CSI Effect is changing the manner in which forensic evidence is
presented in court, with some prosecutors believing they must make their
presentation as visually interesting and appealing as such presentations appear
to be on television. Some are concerned that the conclusiveness and finality of
the manner in which forensic evidence is presented on television results in
jurors giving more or less credence to the forensic experts and their testimony
than they should, raising expectations, and possibly resulting in a miscarriage
of justice. The true effects of the popularization of forensic science
disciplines will not be fully understood for some time, but it is apparent that
it has increased pressure and attention on the forensic science community in
the use and interpretation of evidence in the courtroom.
8 Leading Causes of Wrongful
Conviction:
-
1. Eyewitnes misidentification
-
2. Forensic blood analysis
-
3. Police misconduct
-
4. Defective/fraudulent science
-
5. False confessions
-
6. False witness testimony
-
7. Informants
-
8. DNA inconclusion
Forensic Associations and Societies:
American
Academy of Forensic Sciences
American
Board of Criminalistics
American
Board of Forensic Anthropology
American
Board of Forensic Odontology
American
Board of Forensic Toxicology
American
Society for Quality
American
Society for Testing and Materials
American
Society of Crime Laboratory Directors
American
Society of Questioned Document Examiners
AOAC
International
Association
of Firearm & Tool Marks Examiners
Association
of Forensic Quality Assurance Managers
California
Association of Criminalistics
Canadian
Society of Forensic Sciences
Council
of Federal Forensic Crime Laboratory Directors
Forensic
Science Society
International
Association for Identification
International
Association of Arson Investigators
International
Association of Bloodstain Pattern Analysts
International
Association of Coroners and Medical Examiners
International
Association of Forensic Nurses
International
Association of Forensic Toxicologists
Mid-Atlantic
Association of Forensic Scientists
Midwestern
Association of Forensic Scientists
National
Association of Medical Examiners
National
Center of Forensic Science
National
Forensic Science Technology Center
New
Jersey Association of Forensic Scientists
Northeastern
Association of Forensic Scientists
Northwest
Association of Forensic Scientists
Society
of Forensic Toxicologists
Southern
Association of Forensic Science
Southwestern
Association of Forensic Scientists
Wisconsin
Association for Identification
_______________________________
Above Highlights from:
- Strengthening Forensic Science in
the United States: A Path Forward (pdf)
Other University Courses of Interest:
- Introduction to Forensic Science -
University of Strathclyde
- Forensic Psychology - The Open
University
- Forensic Science and Criminal
Justice - University of Leicester
- Identifying the Dead - University
of Dundee
