Forensic Techniques

1. Forensic Techniques

2. What is Forensic Science? • Forensic comes from the Latin word forensis. • It means: for public discussion or debate. • Forensic science is science used in public, in a court or in the justice system. Any science, used for the purposes of the law, is a forensic science.

3. Forensic Scientists • Television enhances the image of forensic science. • Forensic scientists are involved in all aspects of criminal cases. • The forensic scientist's goal is to use all available scientific information to determine the facts and, subsequently, the truth. • The forensic scientist might determine: • The validity of a signature on a will, • If a corporation is complying with environmental laws, • The origin of physical evidence at a crime scene.

4. Forensic Scientists • The facts developed by forensic scientists are based on scientific investigation, not circumstantial evidence or the sometimes unreliable testimony of witnesses. • The work of the forensic scientist can prove the existence of a crime or makes connections to a crime.

5. Forensic Scientists • The forensic scientist provides information and expert opinion to investigators, attorneys, judges, and juries which is helpful in determining the innocence or guilt of the accused. • Forensic scientists work closely with police officers, sheriff's deputies, prosecuting and defense attorneys, DEA, CIA, and FBI agents, immigration workers, and crime scene investigators, to name a few.

6. Techniques • Forensic scientists use a variety of techniques in their investigations. • The next 8 slides provide examples of forensic techniques.

7. Firearms and Toolmarks • Typically, this includes matching bullets to the gun that fired them. • Toolmark identification involves the identifying characteristics between tools, such as a pry bar, and the object on which it is used, such as a door frame. • Also included in the category are explosives and imprint evidence.

8. Forensic Profiling • When a specially trained psychiatrist or investigator can examine certain crime scenes to come up with a personality profile of the offender.  

9. Document Examination • This discipline involves all special relationships that may exist between document and inscription and how it relates to a person or sequence of events. • This includes forgery, counterfeiting, and handwriting analysis.

10. Autopsy • Done by a medical examiner • To determine cause of death • Includes external exam and photos • Followed by extensive internal exam: • Organs are removed, weighed and examined • Tissues and fluids are analyzed for abnormalities, presence of drugs, etc.

11. DNA Typing • DNA code varies from one individual to the next • Scientists can link a strand of DNA to an individual • DNA can be identified from hair, blood, or body fluid stains • Provides powerfully compelling evidence

12. Forensic Anthropology • Examination of skeletal remains • Tells if male or female, how the person lived, past illness or debilitation, clues to occupation • Bones can tell us: • Age at time of death • Gender • Race • Height

13. Odontology • Teeth – no other body part lasts longer • In fires, often the only thing remaining • No two people have identical teeth • Dental records are needed to compare to the evidence • Teeth useful in determining a subject’s age

14. Blood • Chemical test can determine if substance (stains) is really blood • Another test determines if it is animal or human blood • Can determine gender from blood evidence

15. Forensics and investigation • American’s Missing • 2,300 people are reported missing each day • Reports of missing persons have increased sixfold in the past 25 years, from roughly 150,000 in 1980 to about 900,000 this year

16. Forensic Science- involves finding the facts of the case that uses technology to uncover scientific evidence • Forensic Medicine-applied to medical science to legal problems and multiple science specialties