Chapter 1Introduction to Forensic Science

Definition and Scope Forensic science is the application of

science to law Applies the knowledge and technology of

science for the definition and enforcement of laws

Supplies accurate and objective information that reflects the events that have occurred at the crime

The terms “Criminalistics” and “Forensic Science” can be used interchangeably.

History Mathieu Orfila –

father of toxicology; formed treatise on the detection of poisons and their effects on animals (1814)

Alphonse Bertillon – first system of personal identification called anthropometry – a procedure of taking s series of body measurement as a means of distinguishing one individual from another (1879)

Francis Galton – first definitive study of fingerprints and developed methodology of classifying them for filing; published Finger Prints in 1892

Leone Lattes – in 1915, he devised a simple procedure for determining blood group of dried bloodstain

Calvin Goddard (1891-1955)– used a comparison microscope to analyze bullets; requires a comparison of the crime scene bullet to one test-fired from the suspect’s gun

Hans Gross (1847-1915) – wrote a book outlining the principles of criminal investigation; he detailed the assistance investigators could expect from microscopy, chemistry, physics, mineralogy, botany, zoology, anthropometry, and fingerprinting

Edmond Locard – persuaded police department in France to give him two attics rooms and two assistants to create a crime lab; founder and director of the Institute of Criminalistics in France; his success sparked the creation of crime labs Vienna, Berlin, Sweden, Finland, and Holland

Locard’s Exchange Principle – the exchange of materials between two objects that occurs whenever two objects come into contact with each other Locard believed that every criminal can be

connected to a crime by dust particles carried from the crime scene

History of Forensic Science 1923 – LAPD creates first crime lab in US 1932 – FBI organized a national crime lab

to offer services to law enforcement agencies in the country; currently, the world’s largest forensic lab

Organization/History of a Crime Lab

Rapid Growth – Necessity of police to secure scientifically

evaluated evidence Increasing crime rate

Drug related crimes DNA profiling

Organization/History of a Crime Lab Federal Crime Labs

FBI (Department of Justice) Drug Enforcement Administration (Department of

Justice) Bureau of Alcohol, Tobacco, Firearms, and

Explosives (Department of Justice U.S. Postal Inspection Service

State Crime Labs Local Crime Labs (municipals/counties)

Service of the Crime Lab Individual crime labs

vary in the type of service it provides based on: Variations in local law Different capacities and

functions of the organization to attached to the crime unit

Budgetary/staffing limitations

Service of the Crime Lab Physical Science Unit Biology Unit Firearms Unit Document Examination Unit Photography Unit Toxicology Unit Latent Fingerprint Unit Polygraph Unit Voice Analysis Unit Evidence-Collection Unit

Functions of Forensic Scientist

1. Collection of Physical Evidence

2. Analysis of Physical Evidence

3. Provision of Expert Testimony

Functions of Forensic Scientist1. Collection of Physical Evidence

Forensic Science begins at the crime scene. If the investigator cannot recognize physical evidence or cannot properly preserve it for laboratory examination, no amount of sophisticated laboratory instrumentation or technical expertise can salvage the situation.

Physical Evidence can achieve its optimum value in criminal investigations only when its collection is performed with a selectivity governed by the collector’s thorough knowledge of the crime lab’s techniques, capabilities, and limitations

2. Analysis of Physical Evidence

A forensic scientist must be skilled in applying the principles and techniques of the physical and natural sciences to the analysis of the many types of evidence that may be recovered during a criminal investigations.

Functions of Forensic Scientist

3. Provision of Expert Testimony

The forensic scientist must also be aware of the demands and constraints that are imposed by the judicial system. The procedures and techniques that are used in the laboratory must not only rest on a firm scientific foundation but also satisfy the criteria of admissibility that have been established by the courts.

Functions of Forensic Scientist

Court Cases Frye v. US Federal Rules of Evidence Daubert v. Merrell Dow Pharmaceutical, Inc Kumho Tire co v. Carmichael Coppolino v. State

Frye v. US(1923)

Set guidelines for determining the admissibility of scientific evidence.

Evidence in question must be “generally accepted” by the scientific community.

Federal Rules of Evidence Governs the admissibility of all evidence,

including expert testimony, in federal courts Many states adopted codes similar to this “A witness qualified as an expert by knowledge,

skill, experience, training, or education, may testify….if (1) the testimony is based on sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.”

Daubert v. Merrell Dow Pharmaceutical, Inc. (1993) Stated that Frye v. US needed to allow for the

courts to make the final judgement on admissibility and validity

Judge must assume responsibility in determining the admissibility and reliability of scientific evidence Theory must be (has been) tested Subject to peer review or publication Rate of error Standards of technique Widespread acceptance

Kumho Tire co v. Carmichael(1999)

The “gatekeeping” role of the trial judge applied not only to scientific testimony but to all expert testimony

Coppolino v. State Techniques that make new discoveries are

still admissible

Provision of Expert Testimony Expert witness – an individual whom the

court determines possesses knowledge relevant to the trial is not expected of the average layperson

Other Forensic Science Services Forensic Pathology

The investigation of sudden, unnatural, unexplained, or violent deaths.

Typically performed by coroners or medical examiners

Primary role is to determine the cause of death; if the cause cannot be found through observation, an autopsy is performed

Cause of death can be classified into five categories: natural, homicide, suicide, accident, or undetermined

Other Forensic Science Services Forensic Pathology

A medical examiner can often estimate the time of death by evaluating the stage of decomposition:

Rigor mortis- immediately following death, when the body relaxes and then becomes rigid without the shortening of the muscles. Usually occurs within the first 24 hours and disappears within 36 hours.

Livor mortis – when the human heart stops pumping and the blood begins to settle in the parts of the body closest to the ground. The skin will appear as dark blue or purple in theses areas. Begins immediately after death and continues for up to 12 hours

Algor mortis – process whereby the body temperature continually cools after death until it reaches room temperature; depending on the environmental conditions, beginning about an hour after death, the body will lose heat at a rate of 1-1.5 degrees Fahrenheit per hour

Potassium levels in ocular fluid -

Other Forensic Science Services Forensic Pathology

Algor mortis – process whereby the body temperature continually cools after death until it reaches room temperature; depending on the environmental conditions, beginning about an hour after death, the body will lose heat at a rate of 1-1.5 degrees Fahrenheit per hour

Potassium levels in ocular fluid (vitreous humor) – after death, cells within the inner surface of the eyeball release potassium into the vitreous humor. By analyzing the amount of potassium present at various intervals after death, the rate at which potassium is released can be determined. This rate can be used to approximate the time of death.

Other Forensic Science Services Forensic Anthropology

The identification and examination of human skeleton remains

Bones undergo an extremely slow breakdown process Can provide several types of individual characteristics:

Origin Sex Approximate age Race Skeletal injury Facial reconstructions

Useful in identifying victims of mass disasters

Other Forensic Science Services Forensic Entomology

The study of insects and their relation to a criminal investigation

Used to estimate time of death Insects will infect body once decomposition begins

and lay eggs; the entomologist can identify the specific insects present in the body and approximate how long a body has been left exposed by examining the stage of development of the larvae

Other Forensic Science Services Forensic Psychiatry

The relationship between human behavior and legal proceedings is examined.

Civil cases – determine whether people are competent to make decisions about preparing wills, settling property, or refusing medical treatment

Criminal cases – evaluate behavioral disorders and determine whether people are competent to stand trial

Also examine behavioral patterns of criminals to help develop a criminal’s behavioral profile

Other Forensic Science Services Forensic Odontology

Identification through dental records Because of teeth enamel’s resilience, the teeth will

outlast tissues and organs as decomposition begins Characteristics of teeth, their alignment, and the

overall structure of the mouth provide evidence for identifying a specific person

Bite marks on a victim can be analyzed and compared to suspect

Other Forensic Science Services Forensic Engineering

Concerns itself with accident reconstruction and causes and origins of fires and explosions