Forensic Science

An Introduction

“I want to be a CSI.”• It’s cool, glamorous and fun. You can drive

humvees, carry a gun, wear expensive clothes and earn lots of money!

The CSI EffectReference to the phenomenon which raises real world expectations of forensic science and crime scene investigation by general public, victims of crime, jury members and even criminals.

'CSI effect' has juries wanting more evidence

By Richard Willing, USA TODAY

CSI shows give 'unrealistic view' By Paul Rincon BBC News science reporter

Understanding the CSI Effect

• Glamorizing the field of forensic science.

• Overstating the accuracy of forensic techniques.

• Exaggerating the abilities of forensic science.

• Inaccurate time frame on when cases get solved.

• Many prosecutors, judges and journalists have claimed that watching television programs such as CSI: has caused jurors to wrongfully acquit guilty defendants when the prosecution presents no scientific evidence in support of the case

ForensicForensic ScienceScience“The application of science to the criminal and civic laws that are enforced by police agencies in a criminal justice system.”

An umbrella term encompassing a myriad of professions that use their skills to help law enforcement officials conduct their investigations.

How and Why is Science Important to Law?

As our society has grown more complex, it has become more dependent on rules of law to regulate the activities of its members

Science has become a potent tool in the enforcement of civil and criminal law.

• Food & Drugs• Automobile Emissions• Purity of water• Levels of toxins

ForensicForensic ScienceScience

The diversity of professions practicing forensic science is illustrated by the eleven sections of The American Academy of Forensic Science.

• Criminalistics• Digital & Multimedia

Sciences• Engineering Sciences• General• Jurisprudence• Odontology• Pathology/Biology• Physical Anthropology• Psychiatry/Behavioral

Sciences• Questioned Documents• Toxicology

History of Forensic Science

Sir Arthur Conan Doyle’s legendary detective Sherlock Holmes applied many of the principles of modern forensic science long before they were adopted widely by police.

History of Forensic Science

Mathieu Orfila (1787 – 1853): Toxicology

Alphonse Bertillon (1853 – 1914): Anthropometry

History of Forensic Science

• Francis Galton (1822 – 1911): Fingerprints• Hans Gross (1847 – 1915): Criminal

Investigation• Leone Lattes (1887 – 1954): Bloodtypes• Calvin Goddard (1891 – 1955):

Comparison Microscope• Albert S. Osborn (1858 – 1946):

Document Examination• Walter C. McCrone (1916 – 2002):

Microscopy Edmond Locard (1877 – 1966): Scientific

Method (Locards Exchange Principle)

Locard Exchange Principle

"Everywhere you go, you take something with you, and you leave something behind."

Locard Exchange PrincipleAnytime there is

contact between two surfaces, there will be a mutual exchange of matter across the contact boundary

Locard Exchange Principle

'Wherever he steps, whatever he touches, whatever he leaves, even unconsciously, will serve as a silent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. All of these and more, bear mute witness against him. This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong, it cannot perjure itself, it cannot be wholly absent. Only human failure to find it, study and understand it, can diminish its value. ‘

-Professor Edmond Locard

1932

The Federal Bureau of Investigation (FBI) crime

laboratory is created.

The Growth of Crime Laboratories

At present, nearly 400 public crime laboratories operate at various levels of government (federal, state, county and municipal) – more than three times the number of crime laboratories operating in 1966.•Supreme court decisions in the 1960’s were responsible for greater police emphasis on securing scientifically evaluated evidence.•Increase in crime rates in the last 40 years.All illicit-drug seizures must be sent to a forensic laboratory for confirmatory chemical analysis before the case can be adjudicated.The advent of DNA profiling

Services of the Crime Laboratory

Five Basic Units1. Physical Science Unit2. Biology Unit3. Firearms Unit4. Document Examination Unit5. Photography Unit

Optional Services•Toxicology Unit•Latent Fingerprint Unit•Polygraph Unit•Voiceprint Analysis Unit•Crime Scene Investigation Unit

Physical Science UnitApplies principles and techniques of chemistry, physics, and geology to the identification and comparison of crime-scene evidence.

•Uses chemical tests and analytical instrumentation to examine items such as:– Drugs– Glass– Paint– Explosives– Soil

Biology UnitIdentification and DNA profiling of: – dried bloodstains – other bodily fluids– hairs– fibers– botanical materials

Firearms Unit

Examines:–firearms–discharged bullets–cartridge cases– shotgun shells–ammunition of all

types– residue on clothing

and other objects

Documentation Examination Unit

• Studies handwriting and typewriting on questioned documents to determine authenticity and source.• Analyze paper and ink• Indented writings• Erasures• Obliterations• Burned or charred documents

Photography Unit• Examines and records

physical evidence• The following may be

required to make invisible information visible:– Digital imaging– Infrared– Ultraviolet light– X-ray photography

• Also aids in the preparation of photographic exhibits for courtroom presentation.

Toxicology UnitExamine body fluids and organs to determine presence or absence of drugs or poisons

Latent Fingerprint Unit• Processes and examines evidence for

latent (not visible to the naked eye) fingerprints – dactyloscopy

Polygraph Unit

• Tool for criminal investigator, not forensic scientist• Handled by people trained in techniques

of criminal investigation and interrogation

Voiceprint Analysis Unit

• Used in cases involving telephone threats or tape-recorded messages• Use a sound spectrograph (an instrument that transforms

speech into a visual graphic display called a voiceprint)

Crime-Scene Investigation Unit

Specially trained personnel dispatched to crime scene (civilian or police) to collect and preserve physical evidence that will later be processed at the crime laboratory.

Other Forensic Services• Forensic Psychiatry• Forensic

Odontology• Forensic

Engineering• Forensic Computer

and Digital Analysis

Forensic PsychiatryExamines the relationship between human behavior and legal proceedings

Forensic Odontology

• The study of teeth as it relates to the law.

• Provides information for identification of victim

• Characteristics of Teeth– overall mouth structure– alignment of teeth– bite mark analysis

Forensic EngineeringEngineers are concerned with failure analysis, accident reconstruction, causes and origins of fires and explosions

Forensic Computer and Digital Analysis

• New and fast- growing field

• Identification, collection, preservation, and examination of information derived from computers and other digital devices

Functions of Forensic Scientist

1) Proper Recognition, Collection, 1) Proper Recognition, Collection, and Preservation of Physical and Preservation of Physical EvidenceEvidence

2) Analysis of Physical Evidence2) Analysis of Physical Evidence

3) Expert Testimony3) Expert Testimony

What do you see?

How about now?