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Introduction to FORENSICS

Intro to Forensics

Christopher Ervin

on 24 October 2016

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Transcript of Introduction to FORENSICS

Introduction to Forensics
Forensic Science is the use of scientific knowledge and methods to answer legal questions.
An investigative team uses inquiry skills to help solve crimes. These skills include observing, inferring, predicting, and developing a hypothesis.
Mr. Ervin
Vista Grande High School
Introduction to Forensics
Observing is using one or more of your senses to gather information. People who investigate crime scenes rely on their senses of sight, smell, and hearing. Investigators rarely use taste or touch.
Inferring - is offering a reasoned opinion based on observation and experience.
Predicting - is stating an opinion about what will happen in the future. Inferences about the future are called predictions.
Developing a Hypothesis - Scientists call a possible explanation for a set of observations a hypothesis. There could be more than one reasonable hypothesis for a given set of facts.
Introduction to Forensics
All of the skills, observation, inferring, prediction and developing a hypothesis are used to gather evidence.
Evidence is something that can be presented in court to make a point during a trial.
Securing the crime scene is an important part of any investigation. There are two ways to secure your crime scene; establish clear boundaries and limit entry to the scene.
Securing and Recording a Crime Scene
Establishing Boundaries: The most common way to secure a crime scene is with yellow tape (crime scene tape). Police can also use ropes, orange traffic cones, or parked patrol cars to set a boundary for a crime scene.
If the crime scene is inside, police seal doors and windows with crime scene tape to ensure entry is not gained and to ensure the chain of evidence. These types of boundaries warn people that do not belong there to STAY OUT!
Controling Entry - The more people that enter a crime scene the more chance there is for trace evidence to be destroyed and for them to contaminate the crime scene with their own personal stuff, such as hair or fingerprints. These types of things can confuse investigators later in the investigation.
Securing a Crime Scene
Recording a Crime Scene
Once the crime scene is secured the investigators must start to collect and process evidence.
There are several ways an investigator can start to record the crime scene - photographs, videos, sketches, and notes or, a combination of these can be used to record a crime scenes details.
Photographs - can record evidence that could be destroyed later, Police can use them to notice details they may have missed the first time through a crime scene. Crime scenes that involve busy streets can not be shut down for a long time so, photos help preserve the conditions at the time the investigators arrived at the crime scene.
Videos - Videos provide a powerful "you are there" experience for members of the jury when the case finally makes it to court. Videos do not show details as clearly as photographs do but are very helpful to an investigative team. While doing the video, the sound is usually off. Investigators do not want to hear the comments of the officers at the scene. When doing a video, investigators will start outside the crime scene and work toward the middle of the area.
Recording a Crime Scene
A sketch is a rough drawing done quickly and without much detail. Sketches do not include every detail at the scene, investigators decide what to include in their sketch and what to leave out. Good sketches should include accurate measurements. The measurements must be accurate to ensure the reliability of the model building later in the investigation.
Scale Drawings can also be used to record a crime scene. These are more detailed and take a longer time to complete.
Written notes and Dictated notes are also productive methods of recording a crime scene. Investigators use one or the other method or at times both. Investigators need to be good readers, writers, speakers and listeners. It is important for any investigator to be able to communicate the details of the investigation to other officers and most important, to the court during the trail.
In a convenience store there are 2 people leaning on the counter talking with the store clerk. After a minute one says we have a gun, give us all of your money, the other customers gasp and shrink back, the clerk hands over the money and laughingly one of the robbers hands back a dollar and tells the clerk to get himself a bag of chips. After the robbers exit the store everyone starts talking. "Did you see the gun?", "Were they both men?", "One was kind of tall, an one was short.", "Maybe one was a girl." When the police arrive, they will find the people who witnessed the crime, they will also find the dollar the robbers left behind. These are two different types of evidence - Direct Evidence and Physical Evidence.
Types of Evidence
Eyewitnesses provide firsthand observations which are known as direct evidence. Direct evidence can be used in court to prove a fact. The clerk in the example could testify in court that there were two robbers.
Direct Evidence
One of the first things that officers do when they arrive at a crime scene is to identify witnesses. They collect names, addresses, and phone numbers. Some witnesses may provide accurate descriptions of what they saw or heard. But what a witness says is not always accurate.
Problems with direct evidence
The descriptions that eyewitnesses give at a crime scene may or may not match. One witness says the person drove a gray car. Another may say the car was red. One witness says the person was wearing boots, another can identify the brand of boot. One recalls what the person said another does not remember what was said.
People's physical abilities, experiences, and emotions can affect their observations. A red car may look gray to a person that is colorblind. Someone works in a shoe store and may recognize a boot brand. Or a witness may be to scared or angry to notice anything. Another problem is that witnesses may be asked to recall events weeks or even months after they happen.
If you were asked to say what you did on a given day last month, could you remember?
Police use some different ways to help a witness supply evidence. A witness may be asked to view a lineup or look at mug shots to help identify suspects.
Lineups and Mug Shots
The Lineup - When is a lineup useful? First, investigators need a likely suspect and then the lineup must be fair. All of the individuals in the lineup must be similar in appearance.
Mug Shots - Mug shots are photos taken when a person is arrested. If a suspect has a previous criminal record, police can show a witness mug shots to help further identify the suspect. The police can speed up the process by narrowing the task. Police can show photos of criminals with a modus operandi, or MO, that fits the crime. This is the Latin term for "mode of operation." A person's MO descibes the way they approaches a task.
As investigators are familiar with the issues associated with direct evidence, so, they try to rely on physical evidence.
Physical Evidence
Physical Evidence is any object that can be used to prove that a fact is true. A lot of times physical evidence can be the key to solving a crime.
Transfer of Evidence
The women in the picture on this slide leave a bit of themselves everywhere they go. YOU DO TOO!
You also move materials from one place to another. You may track mud from the yard into the kitchen on your shoes. You may carry sand back from the beach with you in your bathing suit.
Edmond Locard (1877-1966) - A French Scientist that is given credit for being the first to use evidence that had been "transferred" at a crime scene.
Physical Evidence
Locard's Principle - "Every contact leaves a trace." This idea is called Locard's Principle. Forensic scientists know that there is always a transfer of physical evidence at a crime scene.
Locard's Influence, Locard studied both medicine and law. In 1910, he set up his own police laboratory in France. He worked in a very small attic and had only a few simple instruments. He soon became famous for his research into forensic science. His work inspired other police departments to set up laboratories. In the United States, the FBI set up its first lab in 1932.
Each search is a little different. One rule applies to all crime scene searches, The crime scene team must search in an organized way. The team needs to consider the crime scene and pick a search pattern before they start.
Organizing a Search
Consider the Crime Scene
Some crime scenes are small and some are big. For crimes that take place outside weather can be a serious issue to consider.
Pick a Search Pattern
Search patterns should be designed to cover every inch of the crime scene. A search pattern is picked based on the size of the scene and the size of the objects the team is looking for.
There are a few different ways to set up a search. Investigators can use a strip, or line pattern to search. This type of search is useful for small objects in a large area. A grid pattern is like a stripe pattern search, except that every area is searched twice. In a grid search searchers cross the area the first time, then cross it again at right angles to their first search pattern. The crime scene may also be divided into zones. The zones to be searched are labeled so that searchers can record where they find any evidence at.
Keeping a Chain of Custody
Chain of Custody
Lawyers are famous for getting evidence thrown out of court. Showing an accurate chain of custody can prevent a lawyer making a claim that evidence was miss handled and is no longer useful.
A chain of custody is a written record of who had control of a piece of evidence from the time it was collected.
An accurate chain of custody helps show that an item presented in court is the item that was found at the crime scene. When a CSI packages an item, they label the outside of the container with the date, time, and adds their name or initials
It is not only important to protect any evidence collected at a crime scene, investigators must be protected too.
Protecting the Investigators
Crime scene investigators protect themselves with the following established safety rules and procedures.
A CSI does not eat, drink, chew gum, or put on makeup at a scene.
At some crime scenes goggles, masks and an extra pair of gloves must be worn. If any of those are damaged during the investigation they must be replaced immediately.
A CSI handles all sharp objects with extreme care, whether it be glass, knives, or razor blades.
A helmet and sturdy shoes may also be needed at times. If a crime scene is a building that has damage, there may be falling objects that the CSI must seek protection from.
Crime Scenario
Definition and Scope of Forensic Science
Forensic science in its broadest definition is the application of science to law.
As our society has grown more complex and has become more dependent on rules of law to regulate the activities of its members.
Forensic science applies the knowledge and technology of science to the definition and enforcement of such laws.
Laws are continually being broadened and revised to counter the alarming increase in crime rates. In response to public concern, law enforcement agencies have expanded patrol and investigative functions, hoping to stem the rising crime rates. At the same time they are looking more to the scientific community for advice and technical support for their efforts.
Can the technology that put astronauts on the moon, split the atom, and eradicated most dreaded diseases be enlisted in this critical battle?

Definition and Scope of Forensic Science
Unfortunately science cannot offer final and authoritative solutions to problems that stem from a maze of social and psychological factors. However, science occupies an important and unique role in the criminal justice system. A role that relates to the scientists ability to supply accurate and objective information that reflects the events that have occurred at a crime scene.
Common usage definition for forensic science is this; Forensic science is the application of science to criminal and civil laws that are enforced by police agencies in the criminal justice system.
Forensic science is an umbrella term encompassing a myriad of professions that bring skills to bear to aid law enforcement officials in conducting investigations.

Definition and Scope of Forensic Science
The following demonstrate the diversity of practicing forensics professions as outlined by The American Academy of Forensic Science, the largest forensic science organization in the world;
1. Criminalistics
2. Engineering Science
3. General
4. Jurisprudence
5. Odontology
6. Pathology/Biology
7. Physical Anthropology
8. Psychiatry and Behavioral Science
9. Questioned Documents
10. Toxicology
Even this list of professions is not exclusive. It doesn’t list the skills such as fingerprint examination, firearm and tool mark examination, computer and digital data analysis, and photography.

History and Development of Forensic Science
Forensic science owes its origins first to the individuals who developed the principles and techniques needed to identify or compare physical evidence, and second to those who recognized the need to merge those principles into a coherent discipline that could practically be applied to a criminal justice system.
The roots of forensic science reach back many centuries, and history records a number of instances in which individuals used close observation of evidence and applied basic scientific principles to solve crimes. Not until relatively recently, however, did forensic science take on the more careful and systematic approach that characterizes the modern version.

History and Development of Forensic Science
Early Developments
One of the earliest records of applying forensics to solve criminal cases comes from third century China. The case involved a woman that killed her husband and burned the body, and claiming that he died in an accidental fire. Noticing that the husband’s corpse had no ashes in his mouth, the coroner preformed an experiment to test the woman's story. He burned 2 pigs – one alive and the other dead – then checked for ashes inside the mouth of both pigs. He found ashes in the one that had been alive before being burned, but none inside the mouth of the pig that was dead before being burned. After his experiments the coroner concluded that the man was dead before the woman burned the body.
When confronted with the findings the woman confessed her guilt. The Chinese were also among the first to recognize the potential of fingerprints as a means of identification.

History and Development of Forensic Science
Initial Scientific Advances
As physicians gained a greater understanding of the workings of the body, the first scientific treaties on forensics began to appear, such as the 1978 work “A Treatise on Forensic Medicine and Public Health” by the French physician Francois-Emanuel Fodere. New discoveries in chemistry at this time also helped forensic science take significant strides forward. In 1775, the Swedish chemist, Carl Wilhelm Scheele devised the first successful test for detecting the poison arsenic in corpses. By 1806, the German chemist Valentin Ross had discovered a more precise method for detecting small amounts of arsenic in the walls of a victim’s stomach. The most significant early figure in this area was Mathieu Orfila, a Spaniard who is considered the father of forensic toxicology. In 1884, Orfila published the first scientific treatise on the detection of poisons and their effects on animals. This established forensic toxicology as a legitimate scientific endeavor.
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