Criminalistics as Discipline
Learning Objectives
By the end of this lesson, you should be able to:
Define scientific method.
Recognise the major contributors to the development of forensic science.
Describe how Locard’s exchange principle forms the basis of criminal investigations.
Describe the services of a typical comprehensive crime laboratory in the criminal justice system.
Assign evidence recovered at a crime scene to the appropriate forensics unit.
Demonstrate an understanding of what specialised forensic services, aside from the crime laboratory, are generally available to law enforcement personnel.
Introduction to Criminalistics
Definition of Forensic Science
Forensic science is the application of scientific knowledge and technology to civil and criminal laws enforced by police agencies within the framework of the criminal justice system. Although science cannot completely solve or eradicate crime, it plays a crucial role in uncovering the details and events surrounding criminal acts in a precise and objective manner.
Impact of Forensic Science on Everyday Life
Forensic science has significant implications for everyday life, contributing to public safety and wellbeing in various ways:
Determining if a crime was committed: Forensic scientists gather and analyze evidence to ascertain the occurrence of a crime.
Understanding how a crime was committed: Forensic methods assist in reconstructing crime scenes and understanding the methods employed by offenders.
Establishing the timing of a crime: Analysis of evidence can help identify when a crime occurred.
Sequencing events: Forensic analysis helps to arrange a timeline of events relevant to the case.
Identifying victims: Forensic science plays a critical role in the identification of victims, especially in cases involving fatalities.
Automobile safety: Forensic principles are applied to improve automobile safety standards.
Fire prevention and suppression: Techniques developed through forensic science can aid in fire investigation and safety.
Food and drug safety: Forensic analysis ensures that consumables meet safety standards, preventing the sale of harmful goods.
Public place safety: Forensic methods contribute to maintaining safety in recreational areas such as amusement parks.
Transportation safety: Ensuring the safety of transport systems can be supported through forensic investigations.
The relationship between forensic science and daily living extends beyond its obvious uses; it serves as a vital link connecting scientific research with civil and criminal law enforcement.
Scientific Method and Criminalistics
Understanding the complexities involved in reconciling forensic science with legal standards is critical for criminalists. The scientific method provides a structured approach for producing reliable and objective results in forensic investigations. It is essential for criminalists to adhere to scientific principles while addressing the requirements of the legal system.
History and Development of Forensic Sciences
Forensic science evolved from the methods developed around the classification and comparison of physical evidence. Notable contributors include:
3.1 Media Representation of Forensic Science
The depiction of forensic science in the media influences public perception. Positive aspects include increased awareness and scrutiny of law enforcement practices, while negative aspects involve misrepresentations of crime frequency and types, as well as the public's heightened fear of crime.
Reality Check: A small fraction of evidence collected relates to serious crimes. Many cases are not pursued due to perceived cost or insufficient evidence. Issues with evidence mishandling are prevalent across jurisdictions, impacting investigative thoroughness.
3.2 Sir Arthur Conan Doyle & Mathieu Orfila
Sir Arthur Conan Doyle played a pivotal role in popularizing the application of scientific principles in his Sherlock Holmes novels. He introduced concepts such as serology, fingerprinting, and firearms analysis.
Quote from A Study in Scarlet: "In solving a problem of this sort, the grand thing is to be able to reason backward."
Mathieu Orfila (1787–1853): A prominent figure known as the father of forensic toxicology, Orfila authored the first treatise on poisons and their effects on animals, significantly contributing to forensic toxicology.
Orfila was concerned with how poisons could be misinterpreted in the human body and the implications of arsenic exposure in soil.
3.3 Alphonse Bertillon and Anthropometry
Alphonse Bertillon (1853–1914) established anthropometry as a method for personal identification. He introduced systematic body measurements, which were widely used until the introduction of fingerprint analysis.
Bertillon System: This technique included five primary measurements:
Head length
Head breadth
Length of the middle finger
Length of the left foot
Length of the 'cubit'
Bertillon's work laid the groundwork for organized methods of identifying suspects beyond mere eyewitness accounts.
3.4 Francis Galton and Leone Lattes
Francis Galton (1822–1911) pioneered the classification of fingerprints, significantly enhancing their use in criminal identification. He classified fingerprint patterns and published his findings in "Fingerprints" (1892), establishing the principles of dactyloscopy.
Leone Lattes (1887–1954) developed a method for identifying blood types from dried blood stains, known as Lattes tests, which were crucial for connecting suspects to crimes through blood type analysis.
3.5 Calvin Goddard and Albert S. Osborn
Calvin Goddard (1891–1955), recognized as a leader in the field of ballistics, utilized a comparison microscope for bullet analysis. His advancements helped establish a comprehensive database for ballistic evidence.
Albert S. Osborn (1858–1946) is referred to as the pioneer in the examination of document authenticity, emphasizing the importance of document analysis in legal contexts, particularly with his work "Questioned Documents" published in 1910.
3.6 Walter C. McCrone and Hans Gross
Walter C. McCrone (1916–2002) significantly advanced modern microscopy, especially in applying polarized light microscopy for materials analysis.
Hans Gross (1847–1915): A foundational figure in criminalistics, Gross authored influential texts promoting the integration of science into crime solving, such as his book aimed at law enforcement officials.
3.7 Edmond Locard
Edmond Locard (1877–1966), often considered the father of forensic science, established the first police laboratory in Lyon, France. He introduced Locard's Principle of Exchange, stating, "Any action of an individual… cannot occur without leaving a trace." This principle underscores the fundamental concept of trace evidence in forensic investigations.
Crime Laboratory Services
A crime laboratory provides forensic technology services for investigating criminal evidence. Typical services include:
Physical Science Unit: Analyzes various items, including drugs and explosives.
Biology Unit: Specializes in DNA profiling and biological evidence.
Firearms Unit: Examines firearms and ballistic evidence.
Document Examination Unit: Validates and analyzes various document types.
Photography Unit: Documents crime scenes and evidence using advanced photographic techniques.
4.1 Additional Services
Law enforcement agencies may access specialized forensic services that extend beyond standard crime laboratory capabilities:
Forensic Pathology: Conducts autopsies to determine cause of death.
Forensic Anthropology: Analyzes skeletal remains for identification.
Forensic Entomology: Uses insects to help establish time of death.
Forensic Psychology: Merges psychological principles with legal processes.
Forensic Odontology: Identifies remains through dental records.
Forensic Engineering: Analyzes structural failures and accidents.
Forensic Computer/Digital Analysis: Investigates digital evidence from computer systems, maintaining appropriate chains of custody.
Expectations of a Forensic Scientist
Forensic scientists work behind the scenes, performing crucial tasks that influence investigations. Their main roles include:
Analysis of Physical Evidence: Utilizing various scientific methods to interpret evidence.
Providing Expert Testimony: Discussing findings in court and clarifying the scientific processes involved.
Furnishing Training: Advising law enforcement on evidence recognition, collection, and preservation practices.
5.1 Evidence Admissibility
Judicial admissibility pertains to whether evidence can be presented in court. Two significant standards dictate this:
Frye Standard: Allows evidence based on whether a method is generally accepted within the scientific community.
Daubert Standard: Empowers judges as gatekeepers to evaluate scientific testimony based on criteria such as peer review, error rate, and general acceptance.
Understanding these evidentiary standards is vital for forensic scientists as it impacts the integrity of judicial processes and helps prevent wrongful convictions.
Learning Objectives By the end of this lesson, you should be able to: - Define scientific method. - Recognise major contributors to forensic science. - Describe Locard’s exchange principle in criminal investigations. - Identify services of a comprehensive crime laboratory. - Assign evidence to appropriate forensic units. - Understand specialized forensic services available to law enforcement.
Introduction to Criminalistics
Definition of Forensic Science Forensic science applies scientific knowledge and technology to laws enforced by police in the criminal justice system. It helps uncover details surrounding crimes in a precise and objective way, even if it cannot fully solve or prevent crime.
Impact of Forensic Science on Everyday Life Forensic science enhances public safety by: - Determining if a crime occurred: Analyzing evidence to confirm crimes. - Understanding crime methods: Reconstructing crime scenes and offender strategies. - Timing crimes: Establishing when crimes happened through evidence. - Sequencing events: Creating a timeline of events in a case. - Identifying victims: Crucial in identifying deceased individuals. - Improving automobile safety: Applying forensic principles for safety standards. - Fire safety: Assisting in investigations and safety protocols. - Food and drug safety: Ensuring consumables meet safety standards. - Public safety in recreational areas. - Transportation safety: Supporting safety in transport systems.
Scientific Method and Criminalistics Understanding how forensic science meets legal standards is important. The scientific method provides a structured way to ensure reliable and objective results in forensic investigations, which must align with legal requirements.
History and Development of Forensic Sciences Forensic science developed from methods of classifying and comparing physical evidence. Notable figures include:
Media Representation of Forensic Science The media influences how the public perceives forensic science, with benefits like increased awareness of law enforcement, but also negatives such as misrepresentations. Reality Check: Only a small fraction of evidence concerns serious crimes, with many cases not pursued due to cost or lack of evidence, and issues with mishandled evidence across jurisdictions.
Key Contributors - Sir Arthur Conan Doyle: Popularized forensic principles through his Sherlock Holmes stories, introducing concepts like serology and fingerprinting.
Mathieu Orfila: Father of forensic toxicology, wrote on poisons and their effects.
Alphonse Bertillon: Established anthropometry for personal identification. - Francis Galton: Pioneered fingerprint classification. - Leone Lattes: Developed methods for blood type identification.
Calvin Goddard: Leader in ballistics, utilized comparison microscopes. - Albert S. Osborn: Pioneer in document authenticity examination.
Walter C. McCrone: Advanced microscopy techniques.
Hans Gross: Integrated science into criminology.
Edmond Locard: Established the first police lab and introduced the Principle of Exchange—any action leaves a trace.