What is Forensic Science?
- Forensic science is science applied to ______problems.
- “Forensic” comes from the Latin language meaning “having to do with argumentation and debating”
- Forensics and Forensic science ARE NOT THE SAME THING.
What is criminalistics?
- Refers to activities of a full-service forensic science laboratory (CSI type of work)
- Examples: DNA fingerprinting, fingerprints, protein analysis, hair and fiber analysis, etc.
Corpus Delicti- Elements of a Crime
- all elements of a crime must be proven “beyond a reasonable doubt”
- must be able to gain a conviction
- Example: Illegal drug possession case:
The crime lab must establish the white powder is cocaine, or that the funny-looking cigarettes contain Cannabis sativa (marijuana)
Example: Drunk driving case:
The crime lab must prove that the person charges had a blood alcohol level above the legal limit.
** No elements of a crime can be worth any conviction unless you persuade a judge, jury or administrative officer**
Trier of fact- The person or persons charged with critically evaluating the facts as presented in a legal case.
i.e. the judge or jury
Forensic Science Databases- have been developed to help forensic science during the investigative phase.
Examples:
- (CODIS) The Combined DNA Indexing System. “Bank” that stores DNA profiles of convicted offenders and suspects in cases
- (AFIS) Automated Fingerprint Identification System. Contains many known fingerprints and fingerprints not yet identified.
- (NIBIN) National Integrated Ballistic Identification Network. Contains image data from bullets and cartridge cases from known weapons seized from solved and unsolved cases.
** All databases are referred to as “forensic files.” **
Brief History of Forensic Science
- First traces can be seen in China in 1250 AD
- Accepted origin is believed to be between 1800 and 1850….. this is when the formal scientific approach was developing
- New foundations in chemistry and medicine
- Microscopes became available
- Doctors carefully dissected bodies to better understand human anatomy
Matthew Orfila- (1787- 1853) French scientist that was called “The father of Forensic Toxicology”
Hans Gross- law professor; in 1893 published the first official book called Handbuch fur Untersuchungsrichter (translated to Criminal Investigation: Application of Scientific Techniques)
· Gross is given credit for the word criminalistics
Alphonse Bertillon - 1890’s; developed a method for criminal identification for the Paris police agencies that was based on body measurements.
· Dead and arrested people had their measurements kept on file (similar to today)
______
Early 1900’s the United States was the leader in forensic science.
1923- oldest forensic laboratory was created in Los Angeles by August Vollmer.
1932- Federal Bureau of Investigators (lead by J. Edgar Hoover) organized a national lab that offered forensic services to all law enforcement agencies.
· World’s largest forensic lab
· Performs over 1 million tests each year
1981- FBI started the “Forensic Science Research and Training Center”
· Lab was dedicated to develop new and reliable scientific methods that can be applied to forensic science
The Organization of a Crime Laboratory
Today, there are 320 public crime laboratories operating in the United States (3x the number versus 1966)
· DNA crime labs have been increased over the last 20 years. Why?
The FBI operates:
Drug Enforcement Administration: (Department of Justice)
(DEA) – DEA is responsible for the analysis of drugs seized in violations of the law.
Bureau of Alcohol, Tobacco, and Firearms (Department of Treasury)-) is- is responsible for analyzing beverages and documents relating to tax enforcement as well as examining weapons, explosives and related evidence.
Services of the Crime Lab
- not all crime labs are considered “full service”.
- A “full service” crime lab has the following laboratories.
Physical Science Unit- applies- applies principles of chemistry, physics and geology to compare crime scene evidence.
Subunits:
· Drug Identification
· Mineral Analysis
· Trace Evidence
Biology Unit- staffed with biologists and biochemists that apply their knowledge to DNA profiling of dried bloodstains, body fluids, hair, fibers and botanical materials.
Firearms Unit- Examination of firearms, discharged bullets, cartridge cases, shotgun shells. “GSR” and “tool-marks” on clothes is also in the Firearms Unit jurisdiction.
Document Examination Unit- handwriting and typewriting on questioned documents, paper and ink examination, erasures and burned/charred documents.
Photography Unit- complete photographic laboratory that uses specialized photographic techniques such as digital imaging, infrared, ultraviolet, X-ray photography to make information visible to the naked eye. This unit prepares photos for courtroom presentations.
Toxicology Unit- Body fluids and organs are examined to determine the presence or absence of drugs and poisons.
Latent Fingerprint Unit- responsible for processing and examining evidence for latent fingerprints.
Polygraph Unit- responsible for performing polygraph (lie detector) tests; responsible for techniques of criminal investigations and interrogation.
Voiceprint Analysis Unit- responsible for telephoned threats and tape-recorded messages. This unit can transform human speech into a “voiceprint” which is then used in the court of law.
· Every person has 2 unique parts of their speech
1. Voice uniqueness lies in the sizes of a person’ nose, vocal cavity, throat and individual vocal chords.
2. The effect of the mouth, lips, teeth, palate and jaw muscles make each person’s speech very unique.
Evidence Collection Unit- responsible for dispatching specially trained personnel to the crime scene to collect and preserve evidence; used in the court of law.
Example: Stokes, Brown, Grissom and Willows on CSI
http://www.csiwiki.cbs.com/page/CSI+Characters/diff/58,59?t=anon
The Functions of the Forensic Scientist
1. Apply the principles and techniques of physical and natural science to analyze evidence.
2. Must understand the demands and constraints of the legal system.
3. Bear witness in a courtroom testimony. The forensic scientist often takes the role of expert witness- individual whom the court sees as very knowledgeable relevant to the trial.
4. Responsible for Recognition, Collection and Preservation of Physical Evidence (often times the patrol man is responsible for evidence collection!!)
Other Forensic Science Services
Forensic Pathology- involves the investigation of sudden, unnatural, unexplained or violent deaths.
Often a forensic pathologist is a medical doctor (coroner or examiner).
Main goal of the pathologist is to perform an autopsy- a medical dissection and examination of a body in order to determine the cause of death.
Questions the pathologist must ask:
· Who is the victim?
· What injuries are present?
· When did the injuries occur?
Why and how were the injuries produced?
5 categories of death:
· Natural
· Homicide
· Suicide
· Accident
· Undetermined
The pathologist uses clues such as rigor mortis- (stiffening of body parts after death) and liver mortis- (collection of blood in areas of the body next to the ground) to determine the earliest possible time of death.
What causes liver mortis?
Algor mortis- condition where the body continually cools after death until it reaches ambient (environmental) temperature.
Body temperature loss: about one hour after death the body loses 1 to 1.5 degrees Fahrenheit per hour until the body reaches ambient temperature.
Forensic pathologists used potassium (K) levels in the ocular fluid (eye fluid) to determine time of death.
After death eye cells release Potassium ions into the eye fluid.
** Food in the stomach can also be used to determine the time of the last meal, thus approximate time of death.
Forensic Anthropology- involves the investigation and identification of human skeletal remains. The Forensic anthropologist also is responsible for making facial reconstructions.
· Human bones are very resistant to breakdown
· Study of bones may
reveal their origin, sex, age,
race and skeletal injury
Example: a female’s pelvis will differ from that of a male because of childbirth capabilities.
Forensic Entomologist- responsible for the study of insects and their relation to criminal investigations.
Ex: When a person dies their decomposing body attracts insects that lay their larvae (eggs) inside orifices of the body.
· The entomologist can identify what species of insects are present and the approximate time since death of the victim.
Example Insect Life-Cycle:
Blow Fly Life Cycle:
Forensic Psychiatry- responsible for the relationship between human behavior and legal trials.
· Determine whether people are competent to make decisions about
-Preparing wills
-Settling property
-Refusing Medical Treatment
-Stand Trial
Forensic Odontology- responsible for information for the identification of victims when the body is left in an un-recognizable state.
Forensic Odontologist’s main focus is teeth.
**Teeth are the hardest substance within the body**
**Teeth are very resistant because of their enamel**
· Teeth will outlast tissues and organs and decompose very slowly.
Forensic Odontologist’s will use dental records and bite marks to identify a specific person.
Forensic Engineering- responsible for failure analysis, accident reconstruction, and causes and origins of fires or explosions.
Forensic Engineers answer the following questions:
· How did an accident or structural failure occur?
· Were the parties involved responsible?
· If so, how were they responsible?
______
***END OF CHAPTER 1 : INTRO TO FORENSIC SCIENCE***