Forensic Science

The application of science to the criminal and civil laws that are enforced by police agencies in the criminal justice system.

Introduction

Key Terms: -Algor Mortis-Autopsy-Expert Witness-Liver Mortis-Locard’s exchange principle-Rigor mortis

History & Development of Forensic Science

Today, many people believe that Sir Arthur Conan Doyle had considerable influence on popularizing scientific crime detection methods through his fictional character Sherlock Holmes.

First Sherlock Holmes novel,” A Study in Scarlet,” was published in 1887.

Sherlock Holmes first applied the principles of :- Serology- -fingerprinting- -firearms identification- - questioned document examination

Who’s Who in Forensic Science

The following people have made major contributions to Forensic Science.

History of Forensic Science

1814: Mathieu Orfila (B:1787-D:1853)-”Father of Forensic Toxicology”-wrote the first scientific paper on the detection of poisons. - Published articles on the classification of poisons and the detection of poisons in bodily fluids, tissues, and organs (toxicology).

1879: Alphonse Bertillon (B:1853-D: 1914)- First scientific system of personal identification (ANTHROPOMETRY- systematic system of taking a series of body measurements as a means of distinguishing one individual from another.)-Replaced by fingerprinting in early 1900’s, after a case showed that two people had the same measurements.

1887: Sir Arthur Conan Doyle

- Publishes his first Sherlock Holmes novel, A Study in Scarlet. The exploits of the main character in his first novel results in a demand for the use of science in more police work.

1892: Francis Galton ( 1822-1911)-First definitive study of fingerprints and developed a method for classifying them. -In 1892, he published a book called Fingerprints.-Explains many different characteristics of fingerprints and how they combine to form a unique print for each person.

1893: Hans Gross ( 1847-1915)-Wrote the first treatise describing the application of scientific discipline to the field of criminal investigation in 1983. -Published the book Criminal Investigation.-Considered by many to be the first Criminologist.

1898: Paul Jeserich- Developed Forensic Chemistry.

1901: Karl Landsteiner-Discovered the ABO Blood Group

1908: The U.S. Bureau of Investigation ( BOI) is formed with 34 agents.

1910: Albert S. Osborn ( 1858-1946)-Developed the fundamental principles of document examination-Author of “Questioned Documents,” in 1910- explains the scientific investigation of a document of uncertain origin such as, counterfeiting, alteration, obscuring, and obliteration of written instruments.

1910:Edmond Locard ( 1877-1966)-Demonstrated how the principles enunciated by Gross could be incorporated within a workable crime laboratory.-Established Locard’s Exchange Principle.-Established a Crime Laboratory in the police department in Lyon, France. -“ Father of Forensic Science”

1915: Leone Lattes ( 1887-1954)-Took Karl Landsteiner’s work with ABO Blood Groups and devised a relatively simple procedure for determining the blood group of a dried blood stains.

1924: The first Crime Laboratory in the United States is set up as part of the Los Angeles Police Department.

1925: Bureau of Forensic Ballistics -Established in New York by C.E. Waite, Calvin Goddard, Phillip Gravelle, and John Fisher.

1929: Calvin Goddard ( 1891-1955)-U.S Army Colonel: refined the techniques for weapon & bullet analysis using a comparison microscope. -Matches the bullets from the St. Valentine’s Day Massacre to the weapons from which they were fired.-“ Father of Firearms Identification”

1932: BOI establishes a forensic crime laboratory.

1935: BOI changes name to the FBIFederal Bureau of Investigation

Walter C. McCrone ( 1916-2002)-Used microscopy, often in conjuncture with other analytical methodologies to examine evidence in thousands of criminal and civil cases.

Locard’s Exchange Principle

“ Every contact leaves a trace”

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Locard’s Famous PrincipleWherever 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 its interpretation can err. Only human failure to find it, study and understand it, can diminish its value.

Illustration of Locard’s Exchange Principle

• A motorist is driving a 2002 Suzuki XL-7 down a country road at night during a rainstorm. He picks up a hitchhiker, stabs him to death with a knife, and drives the sport utility vehicle ( SUV) into the woods to dispose of the body. A few days later the body is found in the woods. How can the police investigating this crime use locard’s exchange principle?

Role of a Forensic Scientist

• As opposed to what is on television, the role of a forensic scientist is not to run around searching for the “bad guy.”

• Role is to analyze physical evidence. • In the past, forensic scientist’s had college degree

in biology, chemistry, or physics. Additionally, with experience in lab work or an apprenticeship.

• Now forensic scientist’s graduate from 4 year universities with degrees in forensic science.

Role of a Forensic Scientist

• Evidence brought to a crime lab Forensic Scientist analyzes it and gives conclusions to the investigator.

• Identification, comparison, probability, reliability of the results.

• Must also testify in court• Can also be called to testify years later so

forensic scientists must keep good notes.

Role of a Forensic Scientist

• “ Expert” – person with special knowledge, skill, experience, training and or education that goes beyond the experience of ordinary members of the public.

• Can give opinion. • Also Forensic scientist can often be asked to

train police officers in a specific area. – Drug hiding capabilities.

Specialized Forensic Science Carreers

• Some Forensic Scientist’s obtain advanced degrees in medicine, toxicology, odontology, pathology, psychiatry, engineering, entomology, and anthropology.

Coroner

• Latin word meaning, “ from the crown.” • Official, appointed by the king, whose job was

determine the cause of a sudden or unexpected death.

• Replaced by the Medical Examiner System in 1915. – A physician who is authorized by state statute to

investigate sudden, unexpected, violent, post of this investigation is to detect the cause and manner of death.

Forensic Pathologist

• Physician with specialized training in determining the cause of death and in forensic science.

• Aid in providing important information uncovered during the examination of the body. ( Time of Death)

• Time of Death can be determined using several methods and is based on many variables. Because of this reason, a range of time is normally given.

• The estimate of how long a person has been dead is called the Postmortem Interval ( PMI)

Forensic Pathologist

• Algor Mortis- the process by which the body cools after death as a result of the loss of heat to the surroundings.

• Nomograph- diagram that allows a complicated mathematical relationship to be solved simply with a ruler.

• For example: a nomograph can be used to estimate the time of death based on the deep rectal temperature of the body, surrounding air temperature, body weight, and various other correction factors such as presence of clothing and submersion in water.

Forensic Pathologist

• Liver Mortis-settling of blood at the lowest point after death.– Since the heart is no longer pumping blood, gravity

causes blood to pool at the lowest point of the body. – Turns a purplish blue. – Process begins as soon as 30 minutes but doesn’t

become permanent until 8 hours after death. – Can be used to determine if the body was moved after

death, or get some idea about the time of death.

Forensic Pathologist

• Liver Mortis- Stiffening of the muscles of the body. – Muscles relax at first and then begin to contract-

chemical reactions. – 2 hours after death, head first and then moves to

the extremities. – Complete after 6 hours and begins to leave the

body after 24 hours. – 40 hours they are completely gone.

Forensic Pathologist

• Autopsy- a surgical procedure that allows a specially trained medical doctor to help determine the previous health of the deceased and the cause of death.

• Latin- ‘ seeing with your own eyes’• Pathologist, with help of a diener, performs the

autopsy.• “Hie locus est ubi mors gaudet succurrere vitae.”• This is the place where death rejoices to teach those

who live.

Autopsies

• Gross examination of the exterior of the body and the sheets or bags used to cover and transport the body.

• Records are made of the - height, weight, name, and visible characteristics.

• Samples of blood, urine, hair and oral swabs are taken. Scapings from under the nails. Body is x-rayed.

The Process

Autopsy Tools

External Examination

Steps of an external examination.1. Photographed. 2. Physical evidence collected off body.3. Samples of hair, nails, etc. are collected.4. Undressed, examined for wounds.

1. Lacerations, abrasions, bruises.

5. Measured, weighed, cleaned1. Including all organs.

Internal Examination

• Steps of an internal examination.1. Incisions

– A “Y” shaped cut from behind each ear and running down the neck, meeting at the breastbone, continuing towards the groin. Most often used in cases of suspected strangulation.

– A “T” shaped cut from each shoulder ,meeting at the breastbone, continuing towards the groin. Used to create a better looking finished product as this cut is not often seen.

– Single vertical cut from throat to groin.• All cut are deviating towards the left.

Internal Examination (cont’d)

2. Cuts1. The chest cavity is cut open using shears.2. The ribs are sawed away, letting them be lifted off the

body, exposing the heart and lungs.3. Removal

1. En masse technique of Letulle – All organs removed at once.

2. En bloc method of Ghon – organs divided into four groups and removed in sections.

4. All removed organs are now weighed and examined for unusual markings or signs.

Forensic Toxicologist

• Studies toxic substances. • A person, usually with an advanced degree,

who detects the presence of poisons or drugs in bodily fluids, tissues, and organs.

• High performance liquid chromatographs, gas chromatographs, and mass spectrometers which can detect extremely minute quantities of toxic or illegal substances in the human body.

Odontologist

Forensic dentist who applies dentistry to police investigations.

• Body that has been severely burned or disfigured, the odontologist can still make a positive identification through dental records.

• 9/11, Oklahoma City Bombing, Train Accidents …mass casualties.

• Bite marks as well.

Forensic Psychiatrist

• Medical doctor who specializes in the application of psychiatry to law.

• Can be asked to develop a profile of a suspect based on available evidence.

• Testify whether or not the suspect is responsible for their actions.

Forensic Engineer

• Applies engineering principles to law. • Often called into cases when there is a

structural failure such as a bridge or building collapse.

• Analyze the structure and determine the cause of a failure

• Complicated accident scenes.

Forensic Entomologist

• Applies the study of insects to law. • Blowfly- lays eggs on dead tissues- attracted to

the chemicals given off by decomposing flesh- begin laying eggs minutes after death- eggs found in nose, ears, and mouth.

• Lifecycle in Textbook.

Forensic Anthropologist

• Performs specialized examination of human skeletal remains or badly decomposed bodies for the purpose of identification.

• Asked to help determine the cause of death, sex, age, post mortem interval, and race.

• Murder or ancient burial site. • Reconstruct facial characteristics of the skull

to aid in the identification process.