1. What is Forensic Science?
Definition, History & Types

2. What is Forensic Science?
While investigating a homicide, Mike carefully dusts a window for fingerprints. As the black powder is spread across the glass, a faint fingerprint begins to appear. Mike carefully lifts the print and takes it back to the lab. When the fingerprint is entered into the computer, a possible match is identified, and the suspect is picked up for questioning. When the suspect is asked how his fingerprints could have ended up at the crime scene, he confesses to the murder. This is an example of using forensic science to solve a crime.

3. The simplest definition of forensic science is any science used within the criminal justice system.
While this definition may be simple, the field of forensic science is anything but. Crime scene investigators and lab technicians use specialized skills and tools to collect, analyze, and present evidence in order to solve a crime or successfully convict the offender.
The increased use of scientific methods to collect and examine evidence has lead to the closure of many criminal cases that could not be solved through old-fashioned detective work alone. New testing methods are even being applied to cold cases, or cases from many years ago that remain unsolved.

4. Forensic science can be used to:
Prove elements of a crime
Verify or discredit victim or suspect statements
Identify decedents or suspects
Establish a connection to a crime or crime scene
Shoe prints confirm the presence of the suspect and can be used to identify them. Shoe prints confirm the presence of the suspect and can be used to identify them.

5. History of Forensic Science
Medical exams to determine cause of death have been used for centuries, but the use of science to investigate crimes and identify criminals began in the mid to late 1800's.
The first attempt to document the identity of offenders was called anthropometry, which consisted of measuring and documenting the offender's body (head, ears, fingers, etc.). By keeping these records, repeat offenders could be identified, even if they gave a false name. It was soon discovered that due to similar characteristics and measurement errors, this method was not as reliable as was hoped.
This method was replaced by dactylography, or the use of fingerprints for identification. Because everyone (including identical twins) has different fingerprints, this method has been extremely successful and is still in use today.

6. The next major advancement in forensic science did not occur until the 1980's when scientists were able to decode human deoxyribonucleic acid (DNA).
This allowed for the identification of a suspect through hair, skin cells, saliva, blood and semen. DNA has become a reliable way to connect a suspect with a crime scene and to identify human remains.
As this science progresses, new collection and testing methods have allowed investigators to get useful DNA samples from very small or degraded specimens.

7. Forensic science is not only used to identify people, but also to locate or recreate a crime scene. Chemicals such as Luminol and Hemident have been developed to identify blood in a crime scene, even if it has been cleaned.
Luminol will glow when it comes in contact with blood or other bodily fluids.
Once the blood is located, blood spatter analysis can be conducted to recreate the scene. Based on the size and shape of a drop of blood, investigators can determine which direction the droplets were traveling or how far the drops fell before hitting the floor. Information from several drops of blood can be used to locate where the victim or suspect was standing when the blood hit the floor.

8. Science has also been an effective way to link a piece of evidence to its source.
We can match a bullet to the gun it was fired from or match a piece of tape from the scene to the original roll from which it was torn.
This is done using microscopic evaluation of the item. Every gun will leave different grooves on a bullet that passes through it. A piece of tape ripped from the roll or a piece of rope cut from the source can be matched when examined under magnification.
The role of science in the criminal justice system is increasing every day and will likely continue to increase in the future.

9. Types of Forensic Science
Anyone that uses a scientific method to collect or evaluate evidence is using forensic science. This can include a crime scene investigator from a local police department who conducts blood spatter analysis or projectile trajectory, or an expert specifically trained in a certain discipline. These experts may fall into fields such as:
Forensic Anthropology - Usually dealing with bones or decomposed bodies
Forensic Odontology - Identification through dental records or matching bite marks on a victim to a certain suspect
Forensic Psychology - Testifying about competency to stand trial, conduct interviews of suspects/witnesses, criminal profiling

10. Medical Examiners or Coroners - Examine bodies to determine manner and cause of death.
Firearms or ballistics experts - Match a bullet or shell casing to a gun
Biologists - Analyze organic matter from the crime scene, extract and decode DNA
Chemists or toxicologists - Evaluate poisons or other chemicals from a body or crime scene

11. It is important to remember that the term forensic science simply means that science is being used by the justice system, so any scientific field could be included if the testing and results are allowed into a civil or criminal court case.

12. The History of Forensic Science: Timeline & Facts
Crime scene analysis is a popular topic for TV shows and movies these days. With all the cool technology and analysis techniques available for forensics, it's hardly surprising.
But even though our cultural fascination with forensic science may be new, the field itself has a long history. Forensic means 'in open court' in Latin, which makes sense since we think of evidence, facts, and clues when we think of forensics.

13. Forensic evidence collection at a crime scene:
There's not one person or event that sparked a forensic revolution, but we can look to certain scientific and technological advances that contributed to what's familiar today. So let's take a journey through history to see how forensic science has grown and developed throughout the years.
The Early Years
Starting with the year 1302 when the first legal autopsies were performed in Italy by Dr. Bartolomeo da Varignana. These were fairly rudimentary because he had only his eyes and tools to help him, but the information gained from examining bodies in this way was an important step.

14. Jump ahead to 1590 when the microscope was invented by Hans and Zacharias Janssen. This was a game changer, as it allowed for finer examination and comparison of things like glass, hair, fiber, and even teeth.
The invention of the microscope greatly advanced the field of forensic science microscope

15. The 1800s
As we leap into the 19th century, things noticeably pick up for the field of forensic science. Though, keep in mind that throughout this time it's still a self-taught field that doesn't have any official standardization or coordination. Some of the major highlights of forensic advances during the 1800s include:
Using evidence documents known as questioned documents
The invention of the polarized light microscope, often used today in fiber analysis
Using photography for criminal identification and crime scene documentation
Identifying insect stage development in corpses to determine the time elapsed since death

16. The year 1832 is when James Marsh developed the first arsenic test
The year 1832 is when James Marsh developed the first arsenic test. Up to this point, arsenic was essentially untraceable, making it a perfect murder weapon.
In 1835, the first bullet comparison was performed. The bullet itself had a small flaw, which was traced back to the mold, leading to the identification of the person who bought, and later shot said bullet.
Fingerprint analysis officially gained traction in the late 1800s fingerprinting
And in 1892, fingerprints finally made an official name for themselves as forensic evidence. Today, fingerprints are what most people first think of when they think of crime scene evidence. But until almost the 20th century, the individuality of a person's fingerprints was only suspected

17. That year marks the discovery of both the first crime solved by fingerprint analysis, and the calculation by Francis Galton that fingerprints had only a 1 in 64 billion chance of being alike.
The 1900s
As we enter the 20th century we see even more developments. In fact, you can pick almost any year in the 1900s and find some new discovery, technology, or technique that contributed to this field.

18. Let's start in It's during this year that the different human blood types, ABO, are discovered by Karl Landsteiner. This allowed crime scene investigators to match blood from a victim to blood at the scene.
In 1902, the first academic curricula for forensic science was developed in Switzerland. In 1905, President Theodore Roosevelt established the FBI, the Federal Bureau of Investigation, and the first forensic police crime lab was created in 1910.

19. In the 1920s, the comparison microscope became a staple in bullet comparison and the first portable polygraph was designed by John Larson and Leonard Keeler. Universities began offering political science and criminalistics courses and degrees in the 1930s, and in 1950 we see the University of California at Berkeley create one of the first criminology/criminalistics academic departments. The formation of the American Academy of Forensic Science in Chicago occurred during that same year.
Other notable moments in the 20th century include:

20. Enactment of the Federal Rules of Evidence
Development of PCR, or polymerase chain reaction
The discovery of DNA analysis and the use of DNA profiling
Creation of the DNA databank
The invention of the breathalyzer

21. Modern Forensics
With the 21st century has come incredible new advances in technology and refinement of forensic techniques. Three-dimensional computer reconstructions of crime scenes, facial recognition software, surveillance camera footage, advances in DNA technology, and even a Footwear Intelligence Technology database for quick identification of footprints are all realities of modern forensic science. And we continue to see the development of specialized branches and disciplines as forensics moves forward into an exciting new era.