Introduction to Forensic Science

The Science Behind Catching Criminals

Forensic Science

• Forensics is the application of science to criminal and civil law enforced by police in a criminal justice system

• It incorporates techniques of chem, bio, physics, geology, computer tech to determine value of crime scene/related evidence

• Pathology, psychology, anthropology, odontology used in areas of knowledge and practice in law enforcement

Criminalistics vs ForensicsCriminalistics

reflects a purelyscientific approach toexamining crimescenes & evidencethat will be for legaljustice.

uses biology,chemistry, physics,geology, etc (this iswhat we will study)

Forensics

uses a variety of techniques & principles to study evidence that will be used in courts of law.

uses not only science but psychology, accounting, computer science, engineering, etc.

Criminalistics is only a part of Forensic Science

Functions of the Forensic Scientist• Of 3 major avenues to solve a

crime (confession, eyewitness accounts, physical evidence) evidence is free of bias or error

• Analyze physical evidence• May be required to testify at a

trial or hearing• Train law enforcement in the

proper recognition, collection, and preservation of physical evidence

History

• One of earliest records Yi Yu Ji (A Collection of Criminal Cases)

• Coroner solved a case • Woman suspected of murdering husband,

burning the body-no ashes in mouth• Burned 2 pigs and checked for ashes in

mouth• Found ashes in pig that was alive before

burned• No ashes in pig dead beforehand• Guilty or not?• Chinese also first to use fingerprints for ID

History

• 1798 “A Treatise on Forensic Medicine and Public Health”

• 1775 Carl Wilhem Scheele?• 1806 Valentin Ross?• 1814 Mathieu Orfila?• 1828 William Nichol?• 1839 Henri-Louis Bayard?• 1853 hemoglobin?• 1863 blood?• 1850’s and 1860’s photography?

History

• Father of Criminal Identification• Alphonse Bertillon (1879)• Anthropometry involved taking a

series of body measurements to tell one person from another

• Was considered the most accurate method for ID until replaced by fingerprinting

Bertillon Measurements

History

• 1892 Francis Galton?• 1893 Hans Gross?• Best known figure in 19th century

Sherlock Holmes? Which newly developed principles did he apply?

• 1901 Dr. Karl Landsteiner?• 1910 Albert S. Osborn?• 1915 Dr. Leone Lattes?

• Edmond Locard (1910) persuaded a police dept to give him 2 attic rooms and assistants to start a police lab

• "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 & understand it, can diminish its value."

• Professor E. Locard, father of Locard's Exchange Principle

History

Twentieth century:

• Dr. Walter C. McCrone?

• Army Colonel Calvin Goddard?

• 1984 Sir Alec Jeffreys?

• Computerized databases on fingerprints, markings on bullets and shell casings?

Overview

• Organization of a Crime Laboratory

• Services of the Crime Laboratory

• Witnesses

• Collecting Evidence

Crime Labs• Are centers for both forensic

investigation of ongoing criminal cases and research for new techniques for the future

• FBI is the largest in the world• Despite FBI lab, US has no

national system of forensic labs• Many local law enforcement

jurisdictions (city, county, state) run their own independent crime labs

• Also can be run by DA, medical examiner

4 Major Federal Crime Labs:

• FBI: offers more than a million exams a yr; used to develop new testing methods; and, used to train personnel

• DEA (Drug Enforcement Administration): analyze drugs seized in violation of federal laws

• Bureau of Alcohol, Tobacco, Firearms, and Explosives:

analyze alcoholic beverages documents relating to alcohol &firearm excise

tax law enforcement Examine weapons & explosives• U.S. Postal Inspection Service: has labs for

crime investigations related to postal service

5 Basic Services of Crime Labs:

Physical Science:Uses chemical, physical,

and geological techniques to identify/ compare crime scene evidence

Examine drugs, glass, paint, explosives, soil, even drug ID, mineral analysis

Biology Unit:

– Analyze:

• DNA profiling on dried blood

• Body Fluids

• Hair

• Fibers

• Identify and compare wood/plants

Firearms Unit:

– Analyze firearms, bullets, casings, shotgun shells, gunpowder residues on garments, approximate distance gun was fired

– Toolmarks

Document Examination Unit:– Determine authenticity and

source of questioned documents• Paper and ink analysis• Handwriting• Typewriting• Indented writing• Obliterations, erasures,

charred documents

Photography Unit:Examine and record

physical evidence at a crime scene

Can use digital imaging, infrared, UV, X-ray

Prepare photo exhibits for court

Optional Services

• Toxicology: determine drug/poison presence

• Latent Fingerprint: process and examine fingerprints

• Polygraph: lie detector• Evidence Collection:

collect/preserve evidence• Voiceprint Analysis: tie voice to

suspect

Expert vs lay witness

• Expert: will need to be educated, have experience, and training relevant to the trial. This person may express personal opinions to significance of special findings

• Lay: must testify on events or observations that come from personal knowledge (must be factual, no personal opinion of witness)

Collecting evidence

• Get trained personnel to the scene

• They are trained to recognize and gather evidence (CSI)

• Many police forces still have not adopted this approach

• If not, officer or detective collects evidence

Forensic Careers (some examples)

• Criminalistics• Forensic Engineering• Forensic Odontology• Forensic Pathology/Biology• Forensic Anthropology• Forensic Psychology and Psychiatry• Forensic Drugs and Toxicology• Document Examination• Digital and Photography Analysis• Ballistics• Forensics Botany