Chapter 8: The Crime Laboratory
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Chapter 8
The Crime Laboratory
Objectives
1. Define and distinguish forensic science and criminalistics.
2. Describe the importance of an investigator’s understanding of crime laboratory
capabilities.
3. List the three measures of effectiveness of crime laboratories and how they relate to the
2009 National Academy of Science (NAS) report on forensic science in the United States.
4. Distinguish the Frye test from the Daubert test, regarding the admissibility of scientific
evidence.
Introduction
A crime laboratory is a scientific organization with a dedicated mission of aiding the process of
criminal justice. It provides this aid by answering, or helping to answer, the vital questions of
whether a crime was committed, how and when it was committed, who committed it, and who
To understand the role of crime laboratories, one must understand their relationship to the
scientific community and to the functions of the criminal justice system. There are two distinct
activities involved in laboratory work. One is the gathering of evidence at the scene of a crime,
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function and responsibilities of a crime laboratory. Although the laboratory is one of the most
valuable tools for a criminal investigator, he/she must be aware of its capabilities and limitations.
It is not uncommon, for example, for an investigator to send evidence to a laboratory and delay
the investigation until the laboratory results are received. Crime laboratories are not intended to
The terms forensic science and criminalistics are often used interchangeably. Forensic science is
that part of science applied to answering legal questions. It is the examination, evaluation, and
explanation of physical evidence in law. Forensic science encompasses pathology, toxicology,
physical anthropology, odontology (dental structure, development, and diseases), psychiatry,
questioned documents, firearms, tool mark comparison, and serology, among other fields. Recent
technological advances have added molecular biology and genetics to this list.
Lecture Notes
I. Crime Laboratories
According to the last Census of Publicly Funded Forensic Crime Laboratories, convened in
2014, there are more than 400 state, municipal, county, and federal crime laboratories operating
in the United States. Most crime laboratories have developed in response to a particular need in a
community or region.
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be the purpose, function, and services of crime laboratories, the American Society of Crime
Laboratory Directors (ASCLD) was formed.
A. Digital Crime Labs
Although many of the digital crime labs servicing the needs of local law enforcement have
B. The Morgue
An often forgotten crime lab is the morgue. A morgue is not just a place that houses the
C. Expectations
It is not unusual to find situations in which investigators not acquainted with the services of
the crime laboratory expect too much from scientific analysis. To some extent, investigators
II. Measures of Crime Laboratory Effectiveness
After two years of listening to sworn testimony, independent research, and investigative work,
the Committee on Identifying the Needs of the Forensic Sciences Community at the National
A. Quality
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Quality is judged largely on the technical capabilities of the laboratory and the abilities of the
personnel who staff the crime lab.
B. Proximity
Most law enforcement agencies cannot afford to staff and maintain their own crime
C. Timeliness
Timeliness, which is extremely important to the positive resolution of the case, is the third
measure of effectiveness of a crime laboratory.
D. Responding to the National Academies of Science (NAS) Report
In the aftermath of the NAS report, a number of initiatives were undertaken to address some
E. Admissibility of Examination Results
In 1923, a federal court rendered a decision in the case of Frye v. United States that ruled
inadmissible the results of a “deception test,” an early version of the polygraph. In the 1970s
the federal rules of evidence were adopted, which provide that if scientific, technical, or other
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the facts of the case.
III. Technologies
The speed at which technological advances with forensic applications are developing, expanding,
and evolving makes their description immediately obsolete. Computerization has increased speed
and reliability of many of the processes formerly manually performed.
A. DNA Analysis
Advances in technology have helped DNA testing to become an established part of criminal
justice procedure. Questions about the validity and reliability of forensic DNA test methods
Deoxyribonucleic acid (DNA) consists of molecules that carry the body’s genetic
information and establish each person as separate and distinct. DNA is generally found in
The more an investigator knows about how DNA can be used, the more powerful a tool it
becomes. Because samples of DNA are easily contaminated, extreme care should be taken
while collecting samples. Several precautions are offered to maintain the integrity of the
sample and the analysis:
• The best recommendation for collecting biological evidence is not to remove the sample
from an object, but rather to collect the object with the sample on it (provided that the
sample can be adequately protected from contamination).
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Just as contamination is an issue in the collection and packaging of evidence containing DNA,
it is a very big issue in the handling of DNA during extraction and examination. Coughing or
sneezing while handling DNA evidence can cause contamination.
The effectiveness of DNA evidence in court depends on the ability of a witness to explain the
probability that no other person, except an identical twin, has the same DNA type as that
discovered on a crime scene sample that identically matches the DNA type of the defendant.
Laboratory accreditation by the ASCLD’s accreditation board in all areas of forensic science
requires that quality-assurance measures be in place at the laboratory. Quality-assurance
standards have been developed for DNA analysis by the FBI’s DNA Advisory Board.
The concept behind “high–sensitivity” labs focuses on low copy number DNA samples (or
samples that have fewer than 150 cells of genetic material) that result from minutia evidence
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(for instance, skin cells left on a smudged fingerprint, saliva traces on a cigarette butt, or
perspiration droplets left on a window).
More recently, forensic investigators have begun using a practice called “familial DNA
B. The Innocence Project
The Innocence Project, founded in 1992, is a nonprofit legal organization founded for the
purpose of exonerating wrongfully convicted people through DNA testing. It is especially
interested in cases in which the defendant was convicted using what they consider “unreliable
methods” and in cases in which the evidence was misrepresented or could have been subject
to DNA analysis. The following section discusses a postconviction DNA case and case
involving exoneration from death row.
Evidence used against Pope in court included a knife found in the defendant’s vehicle that
resembled a knife stolen from the victim’s house and a “voice print analysis” that matched
Pope’s voice to messages the attacker had left on the victim’s answering machine in the
weeks following the attack. He was convicted in 1986 for aggravated sexual assault and was
sentenced to 45 years in prison.
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Pope’s claim of innocence. The case was reopened, and the rape kit was submitted for DNA
testing. The results not only proved that Pope was innocent, but the sample matched another
person already convicted and serving time for rape.
In the mid-1970s in San Francisco, Miriam Slamovich, a concentration camp survivor, was
shot point-blank in the face. She died a month later. On the bedroom window, her killer left a
full, perfect fingerprint that became the object of thousands of hours of manual fingerprint
comparisons over a 10-year period. When San Francisco installed an Automated Fingerprint
Identification System (AFIS), the latent print from the Slamovich case was the first search
made, and a hit was recorded in less than 6 minutes. The killer was in custody the same day.
C. National Integrated Ballistic Information Network Program
A joint program of the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATFE) and
the FBI, the National Integrated Ballistic Information Network (NIBIN) integrates all the
elements of Ceasefire and Brasscatcher (both former ATFE programs) and Drugfire (an FBI
program).
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IV. Handling Evidence in the Laboratory
A. Human Factors
In handling evidentiary materials, laboratory personnel—scientists and technicians alike—
have always been cautious not to disturb or ruin the viability of the materials for any possible
B. Instrumental Analysis
The kinds of evidence subject to laboratory examinations are many and varied. For laboratory
V. ATFE Forensic Science Laboratories
The ATFE of the U.S. Department of Justice maintains five forensic science laboratories. The
ATFE National Laboratory was created by Congress in 1886. The ATFE laboratories, in addition
to analyzing alcohol and tobacco samples, conduct forensic examinations in support of the
bureau’s explosives, bombing and arson, and illegal-firearm-trafficking investigations, along
with major case investigations of state and local authorities.
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VI. The FBI Crime Laboratory
The FBI Crime Laboratory is one of the largest and most comprehensive forensic laboratories
and is the only full-service forensic laboratory.
A. Reference Files
To aid examiners in their work, the FBI laboratory in 1932 established what is now one of the
largest reference collections for helping solve cases. These files are of two types: (1) standard
VII. Problems in Crime Laboratories
Forensic technology such as DNA analysis offers a great deal of hope to crime victims and law
enforcement. And when used and interpreted correctly, it has truly revolutionized the way we
prosecute cases, examine cold cases, and even exonerate wrongfully convicted inmates.
A. Lack of Training
Continuing professional development is necessary for forensic scientists to remain current and
to advance to an elevated level of expertise and responsibility. They are obligated to remain
up to date in their field through specific and continued education and other developmental
activities.
B. Lack of Accreditation
Crime labs must identify a system for establishing its credentials as a forensic laboratory. As
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mentioned earlier, the primary credentialing organization is the American Society of Crime
Laboratory Directors (ASCLD). Whenever a lab applies for accreditation, it has to meet
certain requirements, which include the development and publication of a quality-control
C. DNA Contamination
Contamination is a concern for proper preservation of evidence. DNA evidence must be
collected and packaged separately in individual containers, and each piece of evidence must
D. Sentencing Mistakes and Poor Training
Mistakes not only harm the validity of evidence in cases, but they also cause citizens to lose
confidence in law enforcement and the experts who work in the crime laboratories in their
communities.
E. Backlog of Cases
Backlogs in crime labs are a simple function of supply and demand. Labs are simply unable to
meet the increased demand for DNA analysis created by the following five factors:
• Increasing awareness
F. Scandals and Mistakes within the FBI Crime Lab: The Madrid Bombing Case
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Another widely publicized incident relating to problems within crime labs involves the
allegations made in 1995 by Frederic Whitehurst, a former FBI laboratory supervisory special
He also said that he believed that FBI management retaliated against him for making those
accusations. Yet changes have been made within the FBI laboratory since Whitehurst blew
the whistle on his coworkers. After intense investigation into his accusations, the FBI lab
implemented a formal quality assurance plan and has since been accredited by the ASCLD.
On May 20, the Spanish National Police reported that they had identified the latent print in
question as that of a different individual— an Algerian national living in Spain. As the
information became conflicted between the two agencies, the FBI sent agents to Spain in
order to recover the original latent print. To their surprise, the print had been destroyed.
G. Code of Ethics
The findings of forensic scientists are often the critical element in determining the guilt or
innocence of an individual. The examination, which is the basis of the findings, must be
conducted in accordance with the principles necessary to achieve an unfailing conclusion.
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These ethics codes require competence, quality, training, and integrity on the part of forensic
experts and managers working in every crime laboratory across the country. Unfortunately,
scandal has become commonplace in a realm where science and integrity must be the
hallmarks of competency.