Role and Significance of Forensics

By Sam McDonald


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Definition and Scope of Forensic Science

Forensic science is the application of science to law, both civil and criminal. It can be used for a wide variety of reasons, including the following:

  • Identifying criminals or victims
  • Analyzing causes of death
  • Studying the effects of drugs or poisons on the body
  • Preventing corporate crimes, cyber crimes, and terrorism, among other types of illegal activity

Crime Laboratories

The first crime lab was established by Edmond Locard in England in 1910. Later in 1923, August Vollmer founded the first crime lab in the United States at the Los Angeles Police Department. These institutions gradually grew in number over the 20th century, and today, there are more than 350 crime labs operating at the federal, state, and local levels in the U.S. alone. This increase was motivated by multiple factors, including:

  • The accompanying increase in the crime rate
  • New and changing laws
  • The introduction of advanced weapons
  • The invention of new, more reliable techniques for forensic investigation

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Types of Crime Labs

The Functions of the Forensic Scientist

Forensic scientists must
  1. be skilled in applying the scientific method.
  2. be able to provide expert testimony in court.
  3. be able to train law enforcement pertaining to proper evidence collection.

Forensic Databases

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  • CODIS (Combined DNA Index System) collects DNA profiles.
  • IAFIS (Integrated Automated Fingerprint Identification System) collects fingerprints and is maintained by the FBI.
  • IBIS (Integrated Ballistic Identification System) collects data on firearms and allows investigators to determine whether a bullet is derived from a gun used in a previous crime.
  • PDQ (Paint Data Query) collects automotive paint data.

Crime Scenes and Physical Evidence

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Common Types of Physical Evidence

  • Glass - broken glass is analyzed for color, thickness, and other characteristics
  • Ballistics - include gunshot residue, bullets, rifling marks, etc.
  • Fingerprints
  • Impressions - include shoeprints, tire tracks, bite marks, and tool marks
  • DNA
  • Skeletal remains - bones can be analyzed to determine sex, age, etc.
  • Documents - handwriting, type of paper, and type of ink is analyzed

Examination and Significance of Physical Evidence

Pieces of physical evidence can establish that a crime has been committed or can provide a link between a crime and its victim or perpetrator. They must be photographed and separately packaged to prevent cross-contamination. Forensic techniques, such as chromatography, gel electrophoresis, and analysis for fracture lines, may then be used to examine evidence.

Preserving and Recording a Crime Scene

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To preserve and record a crime scene, forensic investigators must follow the 7 S's:
  1. Secure the scene by arresting the perpetrator, excluding unauthorized persons, and establishing the boundaries of the scene.
  2. Separate the witnesses.
  3. Scan the scene by taking photos.
  4. Sketch the scene.
  5. Search the scene for physical evidence.
  6. Secure the collected evidence by following proper packaging procedures.
  7. Survey the overall crime scene for any additional evidence.

Role of FBI and CSI

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The FBI, or the Federal Bureau of Investigation, is a federal law enforcement agency that investigates domestic crimes on a national level. It was originally established as the Bureau of Investigation in 1908, but it was later renamed in 1935. The father of the FBI was J. Edgar Hoover, a controversial, corrupt leader who for 48 years held the position of the Director of the FBI. Today, it functions primarily as an organized crime laboratory that offers forensic services to all law enforcement.
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A CSI, or crime scene investigator, is a forensic investigator who analyzes the crime scene for physical evidence. CSIs use four types of search methods at a crime scene, including the spiral, grid, strip, and zone search methods. They must take detailed written notes describing the crime scene and documenting the chain of custody for physical evidence. In addition, they must record the crime scene using photography and sketches. They supervise the crime scene as well to make sure it remains unaltered and to ensure that evidence is packaged properly.

Careers in Forensic Science

Crime Scene Investigator

  • Searches the crime scene for physical evidence
  • Records the crime scene through notes, photography, and sketching
  • Supervises evidence collection and packaging

Forensic Toxicologist

  • Studies the effects of poisons and drugs on the human body
  • Determines which drugs were present in a drug-related death
  • Help determine the cause of death

Forensic Pathologist

  • Performs autopsies on dead bodies
  • Determines manner of death
  • Investigates unnatural, unexplained, or violent deaths

DNA Analyst

  • Obtains DNA samples from evidence or from a person's body
  • Analyzes DNA profiles to narrow down possible suspects
  • Identifies unknown bodies through a DNA profile

Additional Careers

  • Bloodstain pattern analyst
  • Polygraph administrator
  • Forensic ballistics expert
  • Forensic documents examiner
  • Forensic anthropologist
  • Forensic entomologist
  • Forensic odontologist
  • Forensic computer scientist

What Is and Is Not Forensic Science?

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Common Misconceptions

Due to the popularity of forensic investigation television shows, many people misunderstand what forensic scientists actually do. The following list demonstrates these misconceptions:
  • Forensic tests, such as DNA analysis, take only a few hours or even minutes to complete on television, whereas many tests in real life are not completed until several weeks have passed.
  • Unlike their TV show depictions, forensic investigators cannot arrest or interrogate crime suspects. Instead, police officers are responsible for arrests.
  • Although fingerprint and DNA matches occur quickly and easily on TV, the actual process takes much longer and requires much more effort than simply finding a match in a database.
  • Forensic technology is often exaggerated and far more advanced on television than their real-life counterparts. For example, enhancing photographs is rarely possible, but it is a common part of many crime dramas.

Fun Facts

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  • Forensic computer scientists can often uncover deleted documents, programs, and other pieces of software from a computer by using programs to recover the software before it is rewritten by newer data
  • Forensic entomologists study insects on dead bodies in order to determine the victims' times of death
  • Forensic science dates as far back as 1235 A.D., in which a Chinese book details how a murderer confessed to his crime after it was discovered that several flies gathered around his recently washed sickle that had been previously stained with blood
  • Fingerprinting replaced forensic anthropometry in the U.S. after two Kansas inmates, Will West and William West, were found to share the same body measurements and appearance
  • Sir Arthur Conan Doyle first popularized forensic investigation dramas in the 19th century with his famous detective character Sherlock Holmes