“In school, every period ends with a bell. Every sentence ends with a period. Every crime ends with a sentence.” —Stephen Wright, comedian
The study and application of science to matters of law.
Includes the business of providing timely, accurate, and thorough information to all levels of decision makers in our criminal justice system.
The word forensic is derived from the Latin “forensis” meaning forum, a public place where, in Roman times, senators and others debated and held judicial proceedings.
Criminalistics vs Criminology
Criminalistics: the scientific examination of physical evidence for legal purposes.
Criminology: includes the psychological angle, studying the crime scene for motive, traits, and behavior that will help to interpret the evidence
Evidence is anything that tends to establish or disprove a fact. Evidence can include documents, testimony, and other objects.
Crime Lab—Basic Services
Physical Science Unit
Document Examination Unit
Crime Lab—Optional Services
Latent Fingerprint Unit
Evidence Collection Unit
Other Forensic Science Services
Ballistics- the science that deals with the motion, behavior, and effects of projectiles, most often firearms and bullets.
Odontology- examination of bite marks and dental identification of corpses.
Pathology- investigation of sudden, unexplained, or violent death.
Entomology- the study of insects
Forensic psychiatry – there are two major areas of criminal evaluations in forensic psychiatry: competency to Stand trial (CST)
and Mental State at the Time of the Offense (MSO).
Anthropology – the study of skeletal remains
Palynology- the study of pollen and spores
Major Crime Laboratories
U.S. Postal Service
U.S. Fish and Wildlife Service
Crime Lab History
First police crime lab in the world was established in France in 1910 by Edmond Locard
First police crime lab in the U.S. opened in 1923 in Los Angeles
The Scientific Crime Detection Lab was founded in Evanston, Illinois in 1929
The first FBI crime lab opened in 1932
Major Developments in Forensic Science History
700s AD—Chinese used fingerprints to establish identity of documents and clay sculptures
~1000—Roman courts determined that bloody palm prints were used to frame a man in his brother’s murder
1149—King Richard of England introduced the idea of the coroner to investigate questionable death
1200s—A murder in China is solved when flies were attracted to invisible blood residue on a sword of a man in the community
1598—Fidelus was first to practice forensic medicine in Italy
1670—Anton Van Leeuwenhoek constructed the first high-powered microscope
1776—Paul Revere identified the body of General Joseph Warren based on the false teeth he had made for him
1784—John Toms convicted of murder on basis of torn edge of wad of paper in pistol matching a piece of paper in his pocket
1859—Gustav Kirchhoff and Robert Bunsen developed the science of spectroscopy.
1864—Crime scene photography developed
1879—Alphonse Bertillon developed a system to identify people using particular body measurements
1900—Karl Landsteiner identified human blood groups
1904—Edmond Locard formulated his famous principle, “Every contact leaves a trace.”
1922—Francis Aston developed the mass spectrometer.
1959—James Watson and Francis Crick discover the DNA double helix
1977—AFIS developed by FBI, fully automated in 1996
1984—Jeffreys developed and used first DNA tests to be applied to a criminal case
People of Historical Significance
Edmond Locard (1877-1966)
Considered the father of criminalistics
Built the world’s first forensic laboratory in France in 1910
Whenever two objects come into contact with each other, traces of each are exchanged.
Crime Scene Team
A group of professional investigators, each trained in a variety of special disciplines.
First Police Officer on the scene
Medics (if necessary)
Medical Examiner or Representative (if necessary)
Photographer and/or Field Evidence Technician
DNA expert toxicologist
forensic odontologist forensic anthropologist
firearm examiner bomb and arson expert
document and handwriting experts fingerprint expert
Scientific Method (as it pertains to criminalistics)
Observe a problem or questioned evidence and collect objective data.
Consider a hypothesis or possible solution.
Examine, test, and then analyze the evidence.
Determine the significance of the evidence.
Formulate a theory based on evaluation of the significance of the evidence
Complex Reasoning Skills
Necessary to Work Through and Solve Crimes:
Deductive and Inductive Reasoning
Comparing and Contrasting
The U.S. Constitution
Common Law or Case Law
Forensic Legal Vocabulary
Statutory law: legislative acts declaring, commanding, or prohibiting something
Case Law or Common law: the body of law made up of judicial opinions and precedents
Stare decisis: “to stand by the decision” (Latin), meaning previous legal decisions are to be followed.
Civil Law: deals with noncriminal suits brought to protect or preserve a civil or preserve a civil or private right or matter.
Criminal Law: regulation and enforcement of rights setting the acceptable limits of conduct in society.
Equity Law: preventative law for cases not covered by common law (i.e., a restraining order)
Administrative Law: includes rules or laws established by governmental agencies such as the IRS, Social Security and the military.
The Bill of Rights
Gives individuals the right:
To be presumed innocent until proven guilty
Not to be searched unreasonably
Not to be arrested without probable cause
Against unreasonable seizure of personal property
To fair questioning by police
To protection from physical harm throughout the justice process
To an attorney
To know any charges against oneself
To cross-examine prosecution witnesses
To speak and present witnesses
Not to be tried again for the same crime
Against cruel and unusual punishment
To due process
To a speedy trial
Against excessive bail
To be treated the same as others, regardless of race, gender, religious preference, country of origin, and other personal attributes
The government may not take away your life, liberty, or property without following appropriate legal procedures.
Probable cause: situation in which a reasonable and prudent person, viewing the available information, would conclude that a crime has been committed by the suspect.
In 1963, Ernesto Miranda, a 23 year old mentally disturbed man, was accused of kidnapping and raping an 18-year-old woman in Phoenix, Arizona. He was brought in for questioning, and confessed to the crime. He was not told that he did not have to speak or that he could have a lawyer present. At trial, Miranda's lawyer tried to get the confession thrown out, but the motion was denied. The case went to the Supreme Court in 1966. The Court ruled that the statements made to the police could not be used as evidence, since Mr. Miranda had not been advised of his rights.
The following is the Miranda warning:
“You have the right to remain silent. Anything you say can and will be used against you in a court of law. You have the right to speak to an attorney, and to have an attorney present during any questioning. If you cannot afford a lawyer, one will be provided to you prior to any questioning>”
Types of Crimes
Forensic Legal Vocabulary
Infraction: very minor offense, and not necessarily a crime. Punishable by warnings, tickets and probation.
Misdemeanor: a minor crime, less than a felony, usually punished with a fine or confinement other than in prison
Felony: a serious crime, such as murder, punishable by more than one year of imprisonment up to execution.
Steps in Pursuing Justice
1. After a crime has been committed, and evidence has been documented, a suspect may be taken into custody.
2. Suspect is booked and informed of Miranda Rights.
3. Within 72 hours they are brought before a judge for an arraignment. The suspect enters their plea of guilty, not guilty, not guilty by reason of insanity, or nolo contendere.
4. A person pleading guilty will be taken to a preliminary (or evidentiary) hearing. No jury is present, and the Judge assigns the sentence.
5. A person pleading not guilty at the preliminary hearing presents evidence to the Judge and the judge determines whether a trial is necessary, sets the trial date and sets the bail.
6. In the case of a felony, a grand jury will be in place of a preliminary hearing and the jury will hear the evidence and decide whether the suspect should be indicted.
7. A defendant may choose to plea bargain with the prosecutor instead of going to trial, or they will tried by a jury to determine guilt or innocence.
Forensic Legal Vocabulary
Booking: a police procedure following arrest. Includes fingerprinting, a photograph, and basic information about the suspect.
Arraignment: the first act in a criminal proceding in which the defendant is brought before the court to hear charges and enter a plea.
Nolo Contendere: latin for “no contest”, the defendant doesn’t actually admit to guilt, but accepts the punishment as if they were guilty.
Preliminary hearing: determines whether a trial is necessary according to evidence presented.
Bail: money put up to guarantee that the defendant will appear in court as directed. A bondsman will pay the bail for a fee of 10% of the bail. If the defendant doesn’t appear at court, bounty hunters will find the suspect to return them to court.
Indict: to formally accuse a person of a crime
Plea bargain: an agreement in which a defendant pleads guilty to a lesser charge and the prosecutor in return drops the more serious charges to avoid the time and cost of a trial.
In order for evidence to be admissible, it must be:
Probative—actually prove something
Material—address an issue that is relevant to the particular crime
Admissibility of Evidence
1923 Frye v. United States
Scientific evidence is allowed into the courtroom if it is generally accepted by the relevant scientific community. The Frye standard does not offer any guidance on reliability. The evidence is presented in the trial and the jury decides if it can be used.
1993 Daubert v. Dow
Admissibility is determined by:
Whether the theory or technique can be tested
Whether the science has been offered for peer review
Whether the rate of error is acceptable
Whether the method at issue enjoys widespread acceptance.
Whether the opinion is relevant to the issue
The judge decides if the evidence can be entered into the trial.
Facets of Guilt
Try to prove:
Means—person had the ability to do the crime
Motive—person had a reason to do the crime (not necessary to prove in a court of law)
Opportunity—person can be placed at the crime
You have no victim to avenge, no guilty or innocent person to ruin or save.
You must bear testimony within the limits of science.”