Introduction. What is forensic science? The science that is applied to the law and criminal proceedings. It applies the knowledge and technology of science.

FORENSIC SCIENCE

Introduction

What is forensic science?

The science that is applied to the law and criminal proceedings.

It applies the knowledge and technology of science for the definition and enforcement of criminal and civil law.

Often referred to as criminalistics

Why is the forensic scientist so important to the justice system?

They have the ability to supply accurate and objective information that reflects the events that have occurred at a crime.

Is Forensic Science only applied to cases involving homicides?

NO!!!Possible needs include:

◦Burglary◦Counterfeiting/art forgery/document forgery◦White collar crime (embezzlement, etc.)◦Computer crime◦Auto accident◦Arson◦Drug enforcement◦Terrorism◦ETC….

Organization of a Crime Lab

Crime labs are not typical to one type of model because they can vary in:◦Size◦# of employees◦Who runs them (ex: police department,

prosecutor/D.A.’s office, universities, or independent agencies in the government)

◦Services they provideCurrently there are over 320 public crime

labs

Organization of a Crime Lab

A typical crime lab has two sets of personnel:◦Field analysts - investigators that go to crime

scenes, collect evidence, and process the scene.

◦Laboratory analysts - scientists or other personnel who run tests on the evidence once it is brought to the lab (i.e., DNA tests, or bullet striations).

Organization of a Crime Lab

In the United States, crime labs may be publicly or privately operated, although private laboratories typically do not respond to crime scenes to collect evidence.

Public crime labs are organized at the city, county, state, or national level.

Organization of a Crime Lab

The federal government has no single law enforcement or investigative agency that has unlimited jurisdiction.

4 major federal crime labs have been created that extend beyond the jurisdictional boundaries of state and local forces.

Federal Crime Labs

1. FBI –maintains the world’s largest crime lab2. Drug Enforcement Administration Labs (DEA)

– responsile for analysis of drugs seized in violation of federal laws

3. Bureau of Alcohol, Tobacco, and Firearms – responsible for analyzing alcoholic beverages and documents relating to tax law enforcement

4. U.S. Postal Inspection Service – concerned with criminal investigations relating to the postal service

Basic Services

Physical Science Unit◦Applies principles and techniques of chemistry,

physics, and geology. ◦Examination of items as diverse as drugs, glass,

paint, explosives, and soil.Biology Unit

◦Staffed with biologists and biochemists for DNA profiling of dried bloodstains and other bodily fluids, comparison of hair and fibers, & identification and comparison of botanical materials such as wood and plants

Basic Services

Firearms Unit◦Examination of firearms, discharged bullets,

cartridge cases, shotgun shells, and ammunition of all types is conducted

◦Garments and other objects are also examined in order to detect firearm discharge residues

Document Examination Unit◦Handwriting and typewriting on questioned

documents are studied to ascertain authenticity and/or source.

◦Analysis of paper and ink

Basic Services

Photography Unit◦Examine and record physical evidence◦Use of digital imaging, infrared, ultraviolet, and

X-ray photography, to make invisible information visible to the naked eye.

Optional Services

Toxicology Unit◦Body fluids and organs are examined to

determine the presence/absence of drugs and poisons

Latent Fingerprint Unit◦Processing and examining evidence for latent

fingerprintsPolygraph Unit

◦Lie detector◦Essential tool of the criminal investigator

Optional Services

Voiceprint Analysis Unit◦Used for cases involving telephoned threats or

tape-recorded messages to tie the voice to a particular suspect.

Evidence-Collection Unit◦Dispatches specially trained personnel (civilian

and/or police) to the crime scene to collect and preserve physical evidence.

Role of the Forensic Scientist

The role of the forensic scientist is twofold: ◦to analyze physical evidence found on a victim

on the scene of a crime and ◦compare it to evidence found on a suspect and

to provide expert testimony in a court of law.

Role of the Forensic Scientist

Because their work product may ultimately be a factor in determining a person’s guilt or innocence, forensic scientists may be required to testify with respect to their methods and conclusions at a trial or hearing.

In this case, they are considered an expert witness (an individual whom the court determines possesses knowledge relevant to the trial that is not expected of the average layperson.

Additional Forensic Services

Forensic Pathology◦Involves the investigation of sudden, unnatural,

unexplained, or violent deaths.◦If a cause cannot be found through observation,

an autopsy is normally performed to establish the cause of death.

Forensic Pathology

After a human body expires, it goes through several stags of decomposition.

Stages of Death:◦ Rigor Mortis – shortening of muscle tissue and stiffening of

body parts in the position they are in when death occurs Manifests within the first 24 hours and disappears before

36 hours◦ Livor Mortis – settling of blood in areas of the body closest to

the ground Early stages of decomposition Due to the heart stop pumping

◦ Algor Mortis – body temperature continually cools after death until it reaches the ambient of room temperature Rate of heat loss due to location, body size, victim’s

clothing, and weather conditions Heat loss: 1-1.5°F / hour

Forensic Pathology

Another helpful method to determine time of death is to determine potassium levels in ocular fluid (vitreous humor)

After death cells within the inner surface release potassium into the vitreous humor (this rate approximates the T.O.D.)

Forensic Anthropology

Concerned primarily with the identification and examination of human skeletal remains

An examination of bones can reveal origin, sex, approximate age, race, and skeletal injury.

Also assist in creating facial reconstructions to aid in the i.d. of skeletal remains or mass disasters (i.e. plane crash)

Forensic Entomology

The study of insects and their relation to a criminal investigation.

Used to estimate the time of death

Forensic Psychiatry

Specialized area in which the relationship between human behavior and legal proceedings is examined

Retained for both civil and criminal litigations

Forensic Odontology

Provide information for the identification of victims when the body is left in an unrecognizable state

Teeth are composed of enamel, the hardest substance within the body and therefore have a resilience that will outlast tissues and organs as decomposition begins

Also used in bite mark analysis (i.e. case of Ted Bundy)

Forensic Engineering

Concerned with failure analysis, accident reconstruction, and causes and origins of fires or explosions